#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 ans=0 , temp=p;
    
    while(temp>m){
        s-=temp;
        temp-=d;
        if(s>=0)
            ans++;
    }
    
    temp=s;
    while(temp>0){
        temp-=m;
        if(temp<0)
            break;
        ans++;
    }
    
    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;
}