# -*- coding: utf-8 -*-
import sys
# nums = list(map(int, input().split()))
n = int(input())
last = 1
count = 0
if n == 1:
    print('1')
    sys.exit()

while(True):
    if last*2 < n:
        last *= 2
        count += 1
    else:
        count += 1
        break

print(count)