#include <bits/stdc++.h>

using namespace std;

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

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;
}