#include <iostream>

using namespace std;

int main()
{
    int a, b, c, d;
    cin >> a >> b >> c >> d;

    int answer = 0;
    for(int i = a; i >= 0; --i){
        if(i*c > b || i*(c+1) > d) continue;
        else {
            answer = i;
            break;
        }
    }

    cout << answer << endl;
    return 0;
}