def main():
    n, m, p, q = map(int, input().split())

    p -= 1
    arr = [m] * 12
    for i in range(q):
        arr[p + i] *= 2

    res = 0
    while n > 0:
        n -= arr[res % 12]
        res += 1
    print(res)


if __name__ == "__main__":
    main()