#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    // Return the number of games you can buy
    int sum=0,i=0;
    while(sum<=s)
    {
        if((p-(i*d))>=m)
            sum=sum+(p-(i*d));
        else
            sum=sum+m;
        i++;
    }
    return (i-1);
    
}

int main() {
    int p;
    int d;
    int m;
    int s;
    cin >> p >> d >> m >> s;
    int answer = howManyGames(p, d, m, s);
    cout << answer << endl;
    return 0;
}