a = eval(input())

print(("A" if a.upper()==a else "a"))
a = eval(input())

print(("A" if a == a.upper() else "a"))
a = eval(input())
print(("A" if a.upper() == a else "a"))

a = eval(input())
print(("A" if a == a.upper() else "a"))

-print(("A" if a.upper() == a else "a")) +print(("A" if a == a.upper() else "a"))