MOD = 10 ** 9 + 7
INF = 10 ** 15

def main():  
    N = int(input())
    if N == 1:
        print(0)
    else:
        ans = N.bit_length()
        X = 1 << ans
        if X == N << 1:
            print(ans - 1)
        else:
            ans += X - N
            print(ans)
if __name__ == '__main__':
    main()