#include <iostream>
#include <string>
#include <cmath>
using namespace std;

int main()
{
    int A, B, C, D;
    cin >> A >> B >> C >> D;
    int a = 0;
    for (a = 0; a <= A; a++)
    {
        if (a * C > B || a + a * C > D)
        {
            break;
        }
    }
    cout << a << endl;
}