n, m = map(int, input().split())
if n == 0 and m == 0:
    print(2)
elif n == 0:
    print(2 << (m-1) ^ 1)
elif m == 0:
    print(2 << (n-1) ^ 1)
elif n == m:
    print(2 << n)
else:
    print((2 << (n-1)) ^ (2 << (m-1)))