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

int main() {
    int a, b, c, d;
    cin >> a >> b >> c >> d;
    for (int i = a; i >= 0; i--) {
        int j = i * c;
        if (j > b || i + j > d) continue;
        cout << i << endl;
        return 0;
    }
}