#include <bits/stdc++.h>
using namespace std;

int main() {
  int N, M, P, Q;
  cin >> N >> M >> P >> Q;
  vector<int> V(12, M);
  for (int i = P - 1; i < P - 1 + Q; i++) V.at(i) *= 2;
  int cnt = 0;
  while (N > 0) N -= V.at(cnt % 12), cnt++;
  cout << cnt << "\n";
}