def sum(a):
    for i in range (1, 10):
        if a//i == 1:
            suma = i
        elif a//i == 1 and a%i == 0:
            suma = i
    return  suma%10+suma//10

def sum(b):
    for i in range (1, 10):
        if a//i == 1:
            sumb = i
        elif b//i == 1 and b%i == 0:
            sumb = i
            sumb%10+sumb//10
    return sumb%10+sumb//10

a = int(input())
b = int(input())
l = sum(a)
m = sum(b)
if l> m:
    print(l)
else:
    print(m)