#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) {
    int temp=s,i;
    for(i=0;s>=0;i++)
        if(p>=m)
        {
            s-=p;
            p-=d;
        }
    else
    {
        s-=m;
    }
    return i-1;
    // Return the number of games you can buy
}

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