#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) {
    // Return the number of games you can buy
    int i=0;
    int cc=0;
    int count=0;
    while(s>0){
        cc=p-i*d;
        if(cc>=m);
        
        else cc=m;
        
        if(s>=cc){
            s-=cc;
        }
        else{
            break;
        }
        i++;
    }
    return i;
}

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;
}