#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 i=0;
    while(1){
        if(s<p)break;
        if(p-d>=m){
            s=s-p;
            p-=d;
            i++;  
        }
        else{
            s=s-p;
            p=m;
            i++;
        }
    }
    return i;
}

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;
}