from collections import deque,defaultdict as dd 

from bisect import bisect,bisect_left,bisect_right,insort,insort_left,insort_right

from itertools import permutations

from datetime import datetime

from math import ceil,sqrt,log,gcd

def ii():return int(eval(input()))

def si():return eval(input())

def mi():return list(map(int,input().split()))

def li():return list(mi())

abc='abcdefghijklmnopqrstuvwxyz'

abd={'a': 0, 'b': 1, 'c': 2, 'd': 3, 'e': 4, 'f': 5, 'g': 6, 'h': 7, 'i': 8, 'j': 9, 'k': 10, 'l': 11, 'm': 12, 'n': 13, 'o': 14, 'p': 15, 'q': 16, 'r': 17, 's': 18, 't': 19, 'u': 20, 'v': 21, 'w': 22, 'x': 23, 'y': 24, 'z': 25}

mod=1000000007

#mod=998244353

inf = float("inf")

vow=['a','e','i','o','u']

dx,dy=[-1,1,0,0],[0,0,1,-1]



def bo(i):

    return ord(i)-ord('a')









# for _ in range(ii()):

    

s=si()

if 97<=ord(s)<=122:

    print('a')

else:

    print('A')



































'''

    Auther: ghoshashis545 Ashis Ghosh

    College: jalpaiguri Govt Enggineering College



'''

from os import path

import sys

from functools import cmp_to_key as ctk

from collections import deque,defaultdict as dd 

from bisect import bisect,bisect_left,bisect_right,insort,insort_left,insort_right

from itertools import permutations

from datetime import datetime

from math import ceil,sqrt,log,gcd

def ii():return int(eval(input()))

def si():return eval(input())

def mi():return list(map(int,input().split()))

def li():return list(mi())

abc='abcdefghijklmnopqrstuvwxyz'

mod=1000000007

#mod=998244353

inf = float("inf")

vow=['a','e','i','o','u']

dx,dy=[-1,1,0,0],[0,0,1,-1]



def bo(i):

    return ord(i)-ord('a')







def solve():

    

    # for _ in range(ii()):



    s=si()

    if 'a'<=s[0]<='z':

        print('a')

    else:

        print('A')



    





















        

if __name__ =="__main__":



    if path.exists('input.txt'):

        sys.stdin=open('input.txt', 'r')

        sys.stdout=open('output.txt','w')

    else:

        input=sys.stdin.readline

    solve()

from collections import deque, defaultdict as dd
from bisect import bisect, bisect_left, bisect_right, insort, insort_left, insort_right
from itertools import permutations
from datetime import datetime
from math import ceil, sqrt, log, gcd


def ii():
    return int(eval(input()))


def si():
    return eval(input())


def mi():
    return list(map(int, input().split()))


def li():
    return list(mi())


abc = "abcdefghijklmnopqrstuvwxyz"
abd = {
    "a": 0,
    "b": 1,
    "c": 2,
    "d": 3,
    "e": 4,
    "f": 5,
    "g": 6,
    "h": 7,
    "i": 8,
    "j": 9,
    "k": 10,
    "l": 11,
    "m": 12,
    "n": 13,
    "o": 14,
    "p": 15,
    "q": 16,
    "r": 17,
    "s": 18,
    "t": 19,
    "u": 20,
    "v": 21,
    "w": 22,
    "x": 23,
    "y": 24,
    "z": 25,
}
mod = 1000000007
# mod=998244353
inf = float("inf")
vow = ["a", "e", "i", "o", "u"]
dx, dy = [-1, 1, 0, 0], [0, 0, 1, -1]


def bo(i):
    return ord(i) - ord("a")


# for _ in range(ii()):
s = si()
if 97 <= ord(s) <= 122:
    print("a")
else:
    print("A")

"""
    Auther: ghoshashis545 Ashis Ghosh
    College: jalpaiguri Govt Enggineering College
"""
from os import path
import sys
from functools import cmp_to_key as ctk
from collections import deque, defaultdict as dd
from bisect import bisect, bisect_left, bisect_right, insort, insort_left, insort_right
from itertools import permutations
from datetime import datetime
from math import ceil, sqrt, log, gcd


def ii():
    return int(eval(input()))


def si():
    return eval(input())


def mi():
    return list(map(int, input().split()))


def li():
    return list(mi())


abc = "abcdefghijklmnopqrstuvwxyz"
mod = 1000000007
# mod=998244353
inf = float("inf")
vow = ["a", "e", "i", "o", "u"]
dx, dy = [-1, 1, 0, 0], [0, 0, 1, -1]


def bo(i):
    return ord(i) - ord("a")


def solve():
    # for _ in range(ii()):
    s = si()
    if "a" <= s[0] <= "z":
        print("a")
    else:
        print("A")


if __name__ == "__main__":
    if path.exists("input.txt"):
        sys.stdin = open("input.txt", "r")
        sys.stdout = open("output.txt", "w")
    else:
        input = sys.stdin.readline
    solve()

+""" +    Auther: ghoshashis545 Ashis Ghosh +    College: jalpaiguri Govt Enggineering College +""" +from os import path +import sys +from functools import cmp_to_key as ctk -abd = { -    "a": 0, -    "b": 1, -    "c": 2, -    "d": 3, -    "e": 4, -    "f": 5, -    "g": 6, -    "h": 7, -    "i": 8, -    "j": 9, -    "k": 10, -    "l": 11, -    "m": 12, -    "n": 13, -    "o": 14, -    "p": 15, -    "q": 16, -    "r": 17, -    "s": 18, -    "t": 19, -    "u": 20, -    "v": 21, -    "w": 22, -    "x": 23, -    "y": 24, -    "z": 25, -} -# for _ in range(ii()): -s = si() -if 97 <= ord(s) <= 122: -    print("a") -else: -    print("A") +def solve(): +    # for _ in range(ii()): +    s = si() +    if "a" <= s[0] <= "z": +        print("a") +    else: +        print("A") + + +if __name__ == "__main__": +    if path.exists("input.txt"): +        sys.stdin = open("input.txt", "r") +        sys.stdout = open("output.txt", "w") +    else: +        input = sys.stdin.readline +    solve()