#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    # Return the number of games you can buy
    buyable = 0
    #canbuy = True
    total = 0
    i = 0
    while (True):
        if (p - (i * d) <= m):
            total += m
        else:
            total += p - (i * d)
        if (total > s):
            return i
            break
        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)