#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

void howManyGames(int p, int d, int m, int s, int answer) {
    // Return the number of games you can buy 
    s = s - p;
    answer++;
    
    if(p > m)
        p = p - d;
    
    if(p > s)
        return answer;
    else if(p == s)
    {
        answer++;
        return answer;
    }     
}

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, answer);
    printf("%d\n", answer);
    return 0;
}