#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,count = 0;
    while(s>0){
        int diff = p-i*d;
        i++;
        if( diff < m ){
            diff = m;
            i--;
           
        }
         s -= diff;
        
        if( s>=0 )
            count++;
       
    }
    return count;
}

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;
}