#include<iostream>
#include<vector>
#include<string.h>
#include<stdio.h>
#include<climits>
#include<map>
#include<math.h>
#include<algorithm>
#define LL long long int
#define P(N) printf("%d\n",N);
#define S(N) scanf("%d",&N);
#define SL(N) scanf("%lld",&N);
#define pb push_back
#define mp make_pair
#define pnl printf("\n");
#define FOR(i,a,b) for (i=a;i<=b;i++)
#define mem(a,val) memset(a,val,sizeof(a))
using namespace std;
int gcd(int a, int b){ int temp; while(b>0) { temp= b; b=a%b; a=temp;}  return a;}
int main() {
    int i,j,t,p,d,m,s;
    cin>>p>>d>>m>>s;
    int cur = p;
    int ans = 0;
    while(true) {
    	if(s >= cur) {
    		ans++;
    		s = s - cur;
    		if(cur - d <= m) {
    			cur = m;
    		} else {
    			cur = cur - d;
    		}
    	} else {
    		break;
    	}
    }
    P(ans)
return 0;
}