import sys
import itertools

def resolve(in_):
    N = int(next(in_))
    if N == 1:
        return 0

    ans = 1
    i = 1

    while True:
        i *= 2
        if i >= N:
            break
        ans += 1

    return ans


def main():
    ans = resolve(sys.stdin)
    print(ans)


if __name__ == '__main__':
    main()