#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    i = 0
    c = 0
    while(c <= s):
        if((p-d*i) > m):
            c += p - d*i
        else:
            c += m
        i += 1
    return i-1

if __name__ == "__main__":
    p, d, m, s = input().strip().split(' ')
    p, d, m, s = [int(p), int(d), int(m), int(s)]
    answer = howManyGames(p, d, m, s)
    print(answer)