def main():
    N = int(input())
    num = get_base_num(N)
    if N != 2 ** num:
        num += 1
    print(num)

def get_base_num(value):
    count = 0
    while value > 2 ** count:
        count += 1
    return count - 1
        

if __name__ == '__main__':
    main()