a,b = input().split()
dic = {
10:'J',
11:'Q',
12:'K'
}
result = []
k = 0
if len(a)>len(b):
	b = b.zfill(len(a))
if len(a)<len(b):
	a = a.zfill(len(b))
a = a[::-1]
b = b[::-1]
for i in range(len(a)):
	if i%2 == 0:
		k = (int(a[i])+int(b[i]))%13
		if k>9:
			k = dic[k]
		result.insert(0,str(k))
	else:
		k = (int(b[i]) - int(a[i]))%10
		result.insert(0,str(k))
print(''.join(result))