def howManyGames(p, d, m, s):
    count = 0
    sumi = 0
    while sumi<=s:
        if p < m:
            sumi = sumi + m
            
        else:
            sumi = sumi + p
            
            p = p - d

        count = count + 1
    return count-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)