#include <bits/stdc++.h>

using namespace std;

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

int main() {
    int p;
    int d;
    int m;
    int s;
    cin >> p >> d >> m >> s;
    howManyGames(p, d, m, s);
    return 0;
}