diff --git a/d23.lua b/d23.lua
new file mode 100644
index 0000000..f8c0115
--- /dev/null
+++ b/d23.lua
@@ -0,0 +1,189 @@
+function get_param(state, arg)
+    local param_mode = state.mem[state.pos] // (10 ^ (arg + 1)) % 10
+    if #state.mem < state.pos + arg then
+        print(string.format("Error: Opcode too short at end of memory: %d", state.pos))
+        os.exit(false)
+    end
+    local arg = state.mem[state.pos + arg]
+    if param_mode == 0 then
+        arg = arg + 1
+    elseif param_mode == 2 then
+        arg = arg + state.relbase
+    end
+    return arg
+end
+
+function read_mem(state, arg)
+    local param_mode = state.mem[state.pos] // (10 ^ (arg + 1)) % 10
+    local arg = get_param(state, arg)
+    if param_mode == 1 then
+        return arg
+    end
+    arg = state.mem[arg]
+    if not arg then
+        return 0
+    end
+    return arg
+end
+
+function write_mem(state, arg, val)
+    local param_mode = state.mem[state.pos] // (10 ^ (arg + 1)) % 10
+    local arg = get_param(state, arg)
+    if param_mode == 1 then
+        print(string.format("Error: Invalid inmediate write: %d", arg))
+    end
+    state.mem[arg] = val
+end
+
+function interpret(state)
+    if not state.mem then
+        state.mem = state
+    end
+    if not state.pos then
+        state.pos = 1
+        state.relbase = 1
+    end
+    if not state.input then
+        state.input = input_stdin
+    end
+    if not state.output then
+        state.output = output_stdout
+    end
+
+    while true do
+        if #state.mem < state.pos then
+            print(string.format("Instruction pointer ran off of memory"))
+            os.exit(false)
+        end
+
+        local opcode = state.mem[state.pos] % 100
+        local instr_size = 1
+
+        if opcode == 1 then
+            write_mem(state, 3, read_mem(state, 1) + read_mem(state, 2))
+            instr_size = 4
+        elseif opcode == 2 then
+            write_mem(state, 3, read_mem(state, 1) * read_mem(state, 2))
+            instr_size = 4
+        elseif opcode == 3 then
+            local val = state.input()
+            if not val then return true end
+            write_mem(state, 1, val)
+            instr_size = 2
+        elseif opcode == 4 then
+            state.output(read_mem(state, 1))
+            instr_size = 2
+        elseif opcode == 5 then
+            instr_size = 3
+            if read_mem(state, 1) ~= 0 then
+                state.pos = read_mem(state, 2) + 1
+                instr_size = 0
+            end
+        elseif opcode == 6 then
+            instr_size = 3
+            if read_mem(state, 1) == 0 then
+                state.pos = read_mem(state, 2) + 1
+                instr_size = 0
+            end
+        elseif opcode == 7 then
+            write_mem(state, 3, read_mem(state, 1) < read_mem(state, 2) and 1 or 0)
+            instr_size = 4
+        elseif opcode == 8 then
+            write_mem(state, 3, read_mem(state, 1) == read_mem(state, 2) and 1 or 0)
+            instr_size = 4
+        elseif opcode == 9 then
+            state.relbase = state.relbase + read_mem(state, 1)
+            instr_size = 2
+        elseif opcode == 99 then
+            return false
+        else
+            print(string.format("Error: Invalid opcode %d at %d", opcode, state.pos - 1))
+            os.exit(false)
+        end
+
+        state.pos = state.pos + instr_size
+    end
+end
+
+function input_stdin()
+    io.stdout:write("> ")
+    return io.stdin:read("n")
+end
+
+function output_stdout(val)
+    io.stdout:write(val)
+    io.stdout:write("\n")
+end
+
+function input_array(array)
+    function inner()
+        return table.remove(array, 1)
+    end
+    return inner
+end
+
+function output_array(array)
+    function inner(val)
+        table.insert(array, val)
+    end
+    return inner
+end
+
+file = io.open(arg[1])
+program = {}
+for num in string.gmatch(file:read(), "(-?%d+),?") do
+    table.insert(program, tonumber(num))
+end
+file:close()
+
+network = {}
+for i = 1, 50 do
+    computer = {mem={table.unpack(program)}, inp={i - 1}, outp={}}
+    computer.input = input_array(computer.inp)
+    computer.output = output_array(computer.outp)
+    table.insert(network, computer)
+end
+
+nat_seen = {}
+nat = nil
+while true do
+    running = false
+    idle = true
+    for _, computer in ipairs(network) do
+        if #computer.inp == 0 then
+            table.insert(computer.inp, -1)
+        else
+            idle = false
+        end
+        if interpret(computer) then
+            running = true
+        end
+        while #computer.outp > 0 do
+            addr = table.remove(computer.outp, 1)
+            x = table.remove(computer.outp, 1)
+            y = table.remove(computer.outp, 1)
+            if addr == 255 then
+                if not nat then
+                    print("Part 1:", y)
+                end
+                nat = {x, y}
+            else
+                dest = network[addr + 1]
+                table.insert(dest.inp, x)
+                table.insert(dest.inp, y)
+            end
+        end
+    end
+    if idle then
+        if nat_seen[nat[2]] then
+            print("Part 2:", nat[2])
+            break
+        end
+        nat_seen[nat[2]] = true
+        table.insert(network[1].inp, nat[1])
+        table.insert(network[1].inp, nat[2])
+    end
+    if not running then
+        break
+    end
+end
diff --git a/d23_input.txt b/d23_input.txt
new file mode 100644
index 0000000..c4a1f1c
--- /dev/null
+++ b/d23_input.txt
@@ -0,0 +1 @@
+3,62,1001,62,11,10,109,2239,105,1,0,1326,825,1367,1827,1091,1157,2208,986,2132,2070,629,763,1895,1569,1431,1235,1264,1198,1126,1602,1761,1660,600,2023,1295,699,1862,1534,1021,854,571,1631,1697,1396,1058,1994,916,668,1965,2171,1730,1928,1466,2101,730,947,885,1501,794,1796,0,0,0,0,0,0,0,0,0,0,0,0,3,64,1008,64,-1,62,1006,62,88,1006,61,170,1106,0,73,3,65,20101,0,64,1,21002,66,1,2,21102,105,1,0,1106,0,436,1201,1,-1,64,1007,64,0,62,1005,62,73,7,64,67,62,1006,62,73,1002,64,2,133,1,133,68,133,101,0,0,62,1001,133,1,140,8,0,65,63,2,63,62,62,1005,62,73,1002,64,2,161,1,161,68,161,1101,0,1,0,1001,161,1,169,101,0,65,0,1102,1,1,61,1102,0,1,63,7,63,67,62,1006,62,203,1002,63,2,194,1,68,194,194,1006,0,73,1001,63,1,63,1106,0,178,21101,210,0,0,105,1,69,2101,0,1,70,1101,0,0,63,7,63,71,62,1006,62,250,1002,63,2,234,1,72,234,234,4,0,101,1,234,240,4,0,4,70,1001,63,1,63,1106,0,218,1105,1,73,109,4,21102,0,1,-3,21101,0,0,-2,20207,-2,67,-1,1206,-1,293,1202,-2,2,283,101,1,283,283,1,68,283,283,22001,0,-3,-3,21201,-2,1,-2,1105,1,263,22102,1,-3,-3,109,-4,2106,0,0,109,4,21102,1,1,-3,21102,1,0,-2,20207,-2,67,-1,1206,-1,342,1202,-2,2,332,101,1,332,332,1,68,332,332,22002,0,-3,-3,21201,-2,1,-2,1106,0,312,22101,0,-3,-3,109,-4,2106,0,0,109,1,101,1,68,359,20101,0,0,1,101,3,68,367,20102,1,0,2,21101,0,376,0,1106,0,436,22102,1,1,0,109,-1,2106,0,0,1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,32768,65536,131072,262144,524288,1048576,2097152,4194304,8388608,16777216,33554432,67108864,134217728,268435456,536870912,1073741824,2147483648,4294967296,8589934592,17179869184,34359738368,68719476736,137438953472,274877906944,549755813888,1099511627776,2199023255552,4398046511104,8796093022208,17592186044416,35184372088832,70368744177664,140737488355328,281474976710656,562949953421312,1125899906842624,109,8,21202,-6,10,-5,22207,-7,-5,-5,1205,-5,521,21101,0,0,-4,21102,1,0,-3,21101,51,0,-2,21201,-2,-1,-2,1201,-2,385,470,21002,0,1,-1,21202,-3,2,-3,22207,-7,-1,-5,1205,-5,496,21201,-3,1,-3,22102,-1,-1,-5,22201,-7,-5,-7,22207,-3,-6,-5,1205,-5,515,22102,-1,-6,-5,22201,-3,-5,-3,22201,-1,-4,-4,1205,-2,461,1105,1,547,21102,1,-1,-4,21202,-6,-1,-6,21207,-7,0,-5,1205,-5,547,22201,-7,-6,-7,21201,-4,1,-4,1106,0,529,21202,-4,1,-7,109,-8,2106,0,0,109,1,101,1,68,564,20102,1,0,0,109,-1,2106,0,0,1101,22651,0,66,1102,1,1,67,1101,598,0,68,1102,1,556,69,1102,1,0,71,1101,0,600,72,1106,0,73,1,1985,1101,0,89681,66,1101,1,0,67,1102,1,627,68,1102,556,1,69,1101,0,0,71,1102,1,629,72,1105,1,73,1,1851,1101,0,35977,66,1102,1,5,67,1101,0,656,68,1101,0,253,69,1102,1,1,71,1102,1,666,72,1106,0,73,0,0,0,0,0,0,0,0,0,0,13,12487,1101,80683,0,66,1102,1,1,67,1102,1,695,68,1102,1,556,69,1101,1,0,71,1101,697,0,72,1105,1,73,1,160,5,266043,1101,0,11071,66,1102,1,1,67,1102,726,1,68,1102,1,556,69,1101,1,0,71,1101,728,0,72,1105,1,73,1,16183,33,66161,1102,1,22073,66,1102,1,1,67,1102,1,757,68,1101,0,556,69,1102,1,2,71,1102,1,759,72,1106,0,73,1,-3,3,185578,42,136954,1101,23971,0,66,1102,1,1,67,1101,790,0,68,1102,1,556,69,1102,1,1,71,1102,792,1,72,1106,0,73,1,125,21,47643,1101,55291,0,66,1101,0,1,67,1102,821,1,68,1102,1,556,69,1101,0,1,71,1101,0,823,72,1106,0,73,1,29443,3,278367,1101,0,18457,66,1102,1,1,67,1101,852,0,68,1102,556,1,69,1102,1,0,71,1101,0,854,72,1105,1,73,1,1347,1101,0,84061,66,1102,1,1,67,1101,881,0,68,1102,556,1,69,1101,1,0,71,1101,0,883,72,1105,1,73,1,1277,8,253588,1102,94399,1,66,1102,1,1,67,1101,0,912,68,1102,1,556,69,1101,1,0,71,1102,914,1,72,1105,1,73,1,761,8,126794,1102,95869,1,66,1101,0,1,67,1102,943,1,68,1101,0,556,69,1101,0,1,71,1102,1,945,72,1106,0,73,1,271,8,63397,1101,66553,0,66,1102,1,5,67,1101,0,974,68,1102,1,302,69,1102,1,1,71,1101,984,0,72,1105,1,73,0,0,0,0,0,0,0,0,0,0,39,287932,1102,1,69779,66,1101,3,0,67,1101,1013,0,68,1102,1,302,69,1102,1,1,71,1102,1,1019,72,1106,0,73,0,0,0,0,0,0,45,66553,1101,89783,0,66,1101,0,4,67,1102,1048,1,68,1101,0,302,69,1101,1,0,71,1102,1056,1,72,1106,0,73,0,0,0,0,0,0,0,0,10,71954,1101,38891,0,66,1101,1,0,67,1102,1085,1,68,1101,556,0,69,1102,2,1,71,1102,1087,1,72,1106,0,73,1,67,45,266212,17,200542,1101,0,76091,66,1102,1,3,67,1102,1,1118,68,1101,302,0,69,1102,1,1,71,1102,1,1124,72,1105,1,73,0,0,0,0,0,0,39,143966,1102,16493,1,66,1101,0,1,67,1102,1,1153,68,1101,0,556,69,1101,0,1,71,1101,1155,0,72,1105,1,73,1,-162,17,100271,1102,88681,1,66,1102,1,6,67,1101,0,1184,68,1102,302,1,69,1102,1,1,71,1102,1196,1,72,1105,1,73,0,0,0,0,0,0,0,0,0,0,0,0,12,195742,1101,0,100271,66,1101,0,4,67,1102,1225,1,68,1101,0,302,69,1102,1,1,71,1102,1,1233,72,1105,1,73,0,0,0,0,0,0,0,0,4,152182,1101,0,25453,66,1101,1,0,67,1102,1262,1,68,1102,556,1,69,1101,0,0,71,1102,1,1264,72,1105,1,73,1,1724,1102,7393,1,66,1101,1,0,67,1101,1291,0,68,1102,556,1,69,1101,1,0,71,1102,1293,1,72,1106,0,73,1,333706,47,16334,1101,0,75479,66,1101,0,1,67,1102,1322,1,68,1101,0,556,69,1102,1,1,71,1102,1324,1,72,1105,1,73,1,21,33,198483,1102,1,79967,66,1102,1,1,67,1101,1353,0,68,1101,0,556,69,1101,0,6,71,1101,1355,0,72,1106,0,73,1,17335,26,23369,4,76091,4,228273,14,59399,14,118798,14,178197,1101,24251,0,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