#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 = s,j = 0,k,l,temp = p;
    while(i >= temp)
    {
        i = i - temp;
        if((temp - d ) >= m )
        {
            
            temp = temp - d;    
            j++;
            
        }
        else
        {   
            temp = m;
            j++;
            
        }
         
    }
    
    return j;   
}

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;
}