#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,cnt=0,amt=0;
    cin>>p>>d>>m>>s;
   
   int i=0,cost;
    for(;;++i){
        cost = ((p-i*d)<m)?m:(p-i*d);
        if(amt+cost>s) break;
        amt+=cost;
        ++cnt;
    }
        
        cout<<cnt;
    return 0;
}