inp = eval(input())



if inp.isupper():

    print("A")

elif inp.islower():

    print("a")

a = eval(input())



if a.isupper():

  print("A")

elif a.islower():

  print("a")
inp = eval(input())
if inp.isupper():
    print("A")
elif inp.islower():
    print("a")

a = eval(input())
if a.isupper():
    print("A")
elif a.islower():
    print("a")

-inp = eval(input()) -if inp.isupper(): +a = eval(input()) +if a.isupper(): -elif inp.islower(): +elif a.islower():