from fractions import gcd

N = int(eval(input()))

print((2*N//gcd(N, 2)))

N = int(eval(input()))

if N % 2 == 0:

    print(N)

else:

    print((N*2))

from fractions import gcd

N = int(eval(input()))
print((2 * N // gcd(N, 2)))

N = int(eval(input()))
if N % 2 == 0:
    print(N)
else:
    print((N * 2))

-from fractions import gcd - -print((2 * N // gcd(N, 2))) +if N % 2 == 0: +    print(N) +else: +    print((N * 2))