/*
FIND YOUR PURPOSE BECOME UNSTOPPABLE---->>> ?????? 
                    ,.
                  ,_> `.   ,';
              ,-`'      `'   '`'._
            ,,-) ---._   |   .---''`-),.
          ,'      `.  \  ;  /   _,'     `,
      ,--' ____       \   '  ,'    ___  `-,
      _>   /--. `-.              .-'.--\   \__
    '-,  (    `.  `.,`~ \~'-. ,' ,'    )    _\
    _<    \     \ ,'  ') )   `. /     /    <,.
  ,-'   _,  \    ,'    ( /      `.    /        `-,
  `-.,-'     `.,'       `         `.,'  `\    ,-'
  ,'       _  /   ,,,      ,,,     \     `-. `-._
  /-,     ,'  ;   ' _ \    / _ `     ; `.     `(`-\
  /-,        ;    (o)      (o)      ;          `'`,
,~-'  ,-'    \     '        `      /     \      <_
/-. ,'        \                   /       \     ,-'
  '`,     ,'   `-/             \-' `.      `-. <
    /_    /      /   (_     _)   \    \          `,
      `-._;  ,' |  .::.`-.-' :..  |       `-.    _\
        _/       \  `:: ,^. :.:' / `.        \,-'
      '`.   ,-'  /`-..-'-.-`-..-'\            `-.
        >_ /     ;  (\/( ' )\/)  ;     `-.    _<
        ,-'      `.  \`-^^^-'/  ,'        \ _<
        `-,  ,'   `. `"""""' ,'   `-.   <`'
          ')        `._.,,_.'        \ ,-'
            '._        '`'`'   \       <
              >   ,'       ,   `-.   <`'
                `,/          \      ,-`
                `,   ,' |   /     /
                  '; /   ;        (
                  _)|   `       (
                  `')         .-'
                    <_   \   /    
                      \   /\(
                        `;/  `
*/
#include<bits/stdc++.h>
using namespace std;
#define speed ios::sync_with_stdio(0);cin.tie(0);
#define ll long long int
#define INF 100000000

//GCD of 2 numbers START
int gcd(int a, int b) 
{ 
    if (b == 0) 
        return a; 
    return gcd(b, a % b); 
}

//Check Prime STARTS
int IsPrime(ll n) 
{  
    if((n%2==0 && n!=2) || n==1)
    return 0;
    for (ll i=3;i*i<=n;i+=2) 
        {
            if (n%i==0) 
            return 0; 
        }
    return 1; 
}

//SIEVE
int sieve(ll N) {
        bool isPrime[N+1];
        for(ll i = 0; i <= N;++i) {
            isPrime[i] = true;
        }
        isPrime[0] = false;
        isPrime[1] = false;
        for(ll i = 2; i * i <= N; ++i) {
             if(isPrime[i] == true) {                    //Mark all the multiples of i as composite numbers
                 for(int j = i * i; j <= N ;j += i)
                     isPrime[j] = false;
            }
        }
    //Count
        /*ll c=0;
        for (int p=2; p<=N; p++) 
        {
            if (isPrime[p]) 
            c++;
        }
        return  c;*/
    //print
        /*for (int p=2; p<=N; p++) 
        {
            if (isPrime[p]) 
            
          cout << p << " "; 
        }
        return 0;
        */
    }
/*
int main(){
	int n;
	cin>>n;
	int a[n];
	for(int i=0;i<n;i++){
		cin>>a[i];
	}
	int sum=0,max=INT_MIN;
	for(int i=0;i<n;i++){
		sum=0;
		for(int j=i;j<n;j++){
			sum+=a[j];
			if(sum>max)
			max=sum;
		}
	}
	cout<<max<<endl;
}
*/

int maxsubarraysum(int a[], int size) 
{ 
    int max_so_far = INT_MIN, max_ending_here = 0; 
  
    for (int i = 0; i < size; i++) 
    { 
        max_ending_here = max_ending_here + a[i]; 
        if (max_so_far < max_ending_here) 
            max_so_far = max_ending_here; 
  
        if (max_ending_here < 0) 
            max_ending_here = 0; 
    } 
    return max_so_far; 
}

int maxSubArraySum(int a[], int size) 
{ 
   int max_so_far = 0, max_ending_here = 0; 
   for (int i = 0; i < size; i++) 
   { 
       max_ending_here = max_ending_here + a[i]; 
       if (max_ending_here < 0) 
           max_ending_here = 0; 
  
       /* Do not compare for all elements. Compare only    
          when  max_ending_here > 0 */
       else if (max_so_far < max_ending_here) 
           max_so_far = max_ending_here; 
   } 
   return max_so_far; 
}
int max_sum_subarray(int arr[],int n){
	int meh=0,msf=INT_MIN;
	for(int i=0;i<n;i++){
		meh=meh+arr[i];
		if(msf<meh)
		msf=meh;
		if(meh<0)
		meh=0;
}
	return msf;
}	


int main(){
	char n;
	cin>>n;
	if(n>=65 && n<=90)
	cout<<'A'<<endl;
	else
	cout<<'a'<<endl;
}

Measured memory_bytes: 3592