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


int main() {
    int a,b,c,d;
    cin>>a>>b>>c>>d;
    int count=0;
    while(d>=0)
    {
        d-=a;
        count++;
        if(a-b>=c)
        {
            a=a-b;
        }
        else
        {
            a=c;
        }
    }
    cout<<count-1;
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}