import math

def main():
    N = int(input())

    if N == 1:
        print(0)
        return

    if N & 1:
        i = N + 1
        n = 1
    else:
        i = N
        n = 0
    while 1:
        i //= 2
        n += 1
        if i & 1:
            break
    n += int(math.log2(i))
    print(n)
main()