Program

input/code.cpp: In function 'int main()':
input/code.cpp:15:3: error: 'vector' was not declared in this scope
   15 |   vector<string> op;
      |   ^~~~~~
input/code.cpp:2:1: note: 'std::vector' is defined in header '<vector>'; did you forget to '#include <vector>'?
    1 | #include <iostream>
  +++ |+#include <vector>
    2 | 
input/code.cpp:15:16: error: expected primary-expression before '>' token
   15 |   vector<string> op;
      |                ^
input/code.cpp:15:18: error: 'op' was not declared in this scope
   15 |   vector<string> op;
      |                  ^~
input/code.cpp:26:3: error: 'reverse' was not declared in this scope
   26 |   reverse(op.begin(), op.end());
      |   ^~~~~~~

#include <iostream>

using namespace std;

long long n;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  if (n % 3 == 0) {
    cout << 0 << '\n';
    return 0;
  }
  vector<string> op;
  op.emplace_back("END");
  while (n > 1) {
    if (n % 2 == 0) {
      op.emplace_back("MUL");
      n /= 2;
    } else {
      n -= 3;
      op.emplace_back("ADD");
    }
  }
  reverse(op.begin(), op.end());
  cout << op.size() << '\n';
  for (auto x : op) {
    cout << x << '\n';
  }
  return 0;
}