#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    int ans=0;
    while(s-p>=0 && p>=m){
        ans+=1;
        s-=p;
        p-=d;
    }
    if(s-p<0){
        return ans;
    }
    else{
        while(s-m>=0){
            ans++;
            s-=m;
        }
    }
    return ans;
}

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;
}