#include <bits/stdc++.h>

using namespace std;
typedef pair<int, int> P;
typedef pair<P, P> P2;

int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  int ans = 0;
  while (a > 0 && b > 0 && d > 0) {
    if (b >= c && c + 1 <= d) {
      ans++;
      b -= c;
      d -= c + 1;
      a--;
    } else {
      break;
    }
  }
  cout << ans << '\n';
  return 0;
}