def main():
    n = int(input())

    if n == 1 or n == 0:
        print(0)
        return

    q = n
    count = 0
    while q > 2:
        q = q // 2
        s = q % 2
        count += 1

    if count**2 == n:
        print(count)
        return

    ans = count + 1

    print(ans)


if __name__ == "__main__":
    main()