#include <bits/stdc++.h>
#define ll long long int
using namespace std;
ll a,b,c,d,e,hsl=0;
int main()
{
cin>>a>>b>>c>>d;
e=a;
while(d-e>=0)
{
hsl++;
d-=e;
if(e-b<c)e=c;
else e-=b;
if(e<c)e=c;
}
cout<<hsl<<endl;

}