#!/bin/python3

import sys

def howManyGames(p, d, m, s):
    # Return the number of games you can buy
    b = 0
    i = 0
    while True:
        # print(b, p if p > m else m)
        b += (p if p > m else m)
        i += 1
        p -= d
        if b == s: break
        if b > s:
            i -= 1
            break
    return i

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)