#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    int sum=0, temp=0, c=0;
    while(sum<=s){
        temp=sum;
        if(c==0){
            temp+=p;
            if(temp<=s){
                sum=temp;
                p-=d;
            }
            else break;
            c++;
            //cout<<"1: "<<sum<<"p: "<<p<<endl;
        }
        else{
            if(p>m) temp+=p;
            else temp+=m;
            if(temp<=s){
                sum=temp;
                if(p>m) p-=d;
                c++;
            }
            else break;
            //cout<<"2: "<<sum<<"p: "<<p<<endl;
        }
    }
    return c;
    // Return the number of games you can buy
}

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;
}