#include<bits/stdc++.h>
using namespace std;
int main()
{
        int p,d,m,s;
        cin>>p>>d>>m>>s;
        int pf=0,c=0,i=0;
        while(pf<=s){
                if((p-i*d)>m)
            pf += p-i*d;
        else
            pf += m;
            i++;
         if(pf<=s) {c++;//cout<<pf<<endl;
                   }
         else break; 
        }
        cout<<c<<endl;
    return 0;
}