#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 count = 0, sum=0;
    while (sum < s){
        //cout<<p<<" "<<sum<<" "<<m<<endl;
        if (p>m){
            sum+=p;
            p-=d;
        }else{
            sum+=m;
        }
        if (sum<=s) count++;
    }
    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;
}