#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
  int A, B, C, D;
  cin >> A >> B >> C >> D;
  // k + kC <= D k <= A kC <= B
  cout << min(D / (1 + C), min(A, B / C)) << "\n";
  return 0;
}