程序a

程序b

a = 2

res = 1

n = int(input())

for i in range(n):

    res = res * a

print(res)

def powr(a, n):

    if n == 1:

        return a

    elif n == 0:

        return 1

    else:

        tmp = powr(a, n // 2)

        return tmp * tmp

a = 2

n = int(input())

print(powr(a, n))