#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,count=0;
    cin>>p>>d>>m>>s;
    while(s>=0){
        if(s-p>=0){
            count++;
            s = s-p;
        }
        else{
            break;
        }
        if(p-d>=m){
            p = p-d;
        }
        else{
            p= m;
        }
    }
    cout<<count;
    return 0;
}