from math import log2,ceil

N = int(input())
seq = [1]*(ceil(log2(N))+1)
for i in range(1,len(seq)):
    seq[i] = seq[i-1]*2
# print(seq)
for i in range(len(seq)-1, -1, -1):
    if seq[i] < N:
        print(i+1)
        break