N = int(input())
if N == 1:
    print(0)
elif N % 2 == 0:
    n = 1
    count = 0
    while 2*n <= N:
        if 2*n == N:
            count += 1
            break
            print(count)

        else:
            n = n*2
            count += 1
            #print(f'{count}回目:{n}') 
    print(count+1)   

else:
    M = N-1
    n = 1
    count = 0
    while 2*n <= M:
        if 2*n == M:
            count += 1
            break
            print(count)
          
        else:
            n = n*2
            count += 1
            #print(f'{count}回目:{n}') 
    print(count+1)