AB = [int(i) for i in input().split()]

s = 0
b = 0
i = 0
for x in AB:
    if i % 2 == 0:
        b = x
    else:
        s += b ** x
    i += 1
    i %= 2

if s % 2 == 0:
    print(':-)')
else:
    print(':-(')