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

signed main () {

    int a, b, c, d;
    cin >> a >> b >> c >> d;
    int cnt = 0;
    int sum = 0;
    while ( a > 0 && b > 0 ) {
        a--;
        if ( b - c < 0 ) break;
        b -= c;
        sum += 1 + c;
        if ( sum > d ) break;
        cnt++;
    }
    cout << cnt << endl;

    return 0;
}