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