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

    if N == 1:
        print(0)
        return
    x = 1
    n = 0
    while x < N:
        x *= 2
        n += 1
    if x == N:
        print(n)
    else:
        while x > N:
            x -= 1
            n += 1
        print(n)
    
main()