a=eval(input())

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

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

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

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