#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 sum=0,c=0;
    while(sum<=s){
        if(p-d<m){
            sum+=p;
            c++;
            p=m;
        }
        else{
            sum+=p;
            c++;
            p-=d;   
        }
    }
    return (c-1);
}

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;
}