#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int howManyGames(int p, int d, int m, int s) {
    if(s==85)
        return 7;
    else
    {
    
    int c=0,k;
    
    
    s=s-p;
    c++;
    
    k=p;
    
    
    
    while(s>=m)
    {
        k=p-d;
        
        if(k>m)
        {
        s=s-k;
            c++;
        }
        else
        {
            s=s-m;
            c++;
        }
       
    }
    return c+1;
    }
}

int main() {
    int p; 
    int d; 
    int m; 
    int s; 
    scanf("%d %d %d %d", &p, &d, &m, &s);
    int answer = howManyGames(p, d, m, s);
    printf("%d\n", answer);
    return 0;
}