diff --git a/day07.cpp b/day07.cpp
index e34911e..79e97a4 100644
--- a/day07.cpp
+++ b/day07.cpp
@@ -22,9 +22,9 @@ template <class R> auto Controller(Machine machine, R const &params) {
 template <class R>
 auto Feed(R &&amps, ValueType start) -> std::optional<ValueType> {
   for (auto &m : amps) {
-    auto i = Step(m);
-    if (auto p = std::get_if<Input>(&i)) {
-      p->pos = start;
+    auto e = Step(m);
+    if (auto i = std::get_if<Input>(&e)) {
+      i->pos = start;
       start = StepOutput(m);
     } else {
       return {};
diff --git a/day23.cpp b/day23.cpp
index 01fd7f2..897de7a 100644
--- a/day23.cpp
+++ b/day23.cpp
@@ -16,10 +16,10 @@ using Packet = std::pair<ValueType, ValueType>;
 using Ethernet = std::deque<std::pair<std::size_t, Packet>>;
 
 auto BuildNetwork(Machine m) -> std::vector<Machine> {
+  auto& i = std::get<Input>(Step(m)).pos;
   std::vector<Machine> machines;
-  for (int i = 0; i < 50; i++) {
+  for (i = 0; i < 50; i++) {
     machines.push_back(m);
-    StepInput(machines.back(), i);
   }
   return machines;
 }
@@ -57,26 +57,22 @@ auto main() -> int {
   std::optional<Packet> nat;
 
   for(;;) {
-    if (ethernet.empty()) {
-      if (nat) {
-        if (nat->second == part2) { break; }
-        part2 = nat->second;
-        Interact(ethernet, machines[0], nat);
-      } else {
-        for (auto && m : machines) {
-          Interact(ethernet, m, {});
-        }
-      }
-    } else {
+    if (!ethernet.empty()) {
       auto [dest, p] = ethernet.front();
       ethernet.pop_front();
       if (dest == 255) {
         nat = p;
         if (!part1) { part1 = p.second; }
-      } else if (dest < 50) {
-        Interact(ethernet, machines[dest], p);
       } else {
-        throw std::runtime_error{"bad destination"};
+        Interact(ethernet, machines.at(dest), p);
+      }
+    } else if (nat) {
+      if (nat->second == part2) { break; }
+      part2 = nat->second;
+      Interact(ethernet, machines[0], nat);
+    } else {
+      for (auto && m : machines) {
+        Interact(ethernet, m, {});
       }
     }
   }