#!/bin/python3

import sys

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

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)