#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    // Return the number of games you can bu
    int count=0;
    while(s>0)
    {
        if(s-p<0)
            break;
        s-=p;
        count++;
        if((p-d)>m)
        p=p-d;
    else
        p=m;
    }
    return count;
}

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;
}