#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int p,d,m,s;cin>>p>>d>>m>>s;
    long count=0;int price=p;
    if(p<=s){count++;s-=p;}else{s-=p;}
    while(1 && s>0){
        if(price-d>=m){price=price-d;}
        else{price=m;}
        if(s>=price){count++;s-=price;}
        else{break;}
    }
    cout<<count;
    return 0;
}