#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 */   
    long a,b,c,d,e=0,f;
    cin>>a>>b>>c>>d;
    if(d>=a){
        while(d>=a){
            d=d-a;
            if(a-b>c)
            a=a-b;
            else{
                a=c;
            }
            e++;
            
        }
    }cout<<e;
    return 0;
}