#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
    if(s<p)
        return 0;
    long int c=0,sum=0;
    while(sum<=s){
        if(p>=m){
            sum+=p;
            p-=d;
            if(sum>s)
                return c;
            c++;
        }
        else
        {
            sum+=m;
            if(sum>s)
                return c;
            c++;
        }
    }
    return c;
}

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;
}