#include <iostream>
using namespace std;
int main() {
  int a, b, c, d, cnt;
  cin >> a >> b >> c >> d;
  cnt = 1;
  while (true) {
    if (a >= cnt || b >= cnt * c || d >= cnt + cnt * c) {
      cnt++;
    } else {
      cout << cnt - 1 << endl;
    }
  }
  return 0;
}