/*
------------------------------------------CAUTIOUS WARNING ------------------------------------------
This is a personalised Template for Nitin under MIT Licence Act 1840 : Do not use it for own use. */

//AUTHOR Nitin
// TASK : Practice 
//--------------------------------HEADERS-------------------------------------------------------------//
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <limits>
#include <string>
#include <cassert>
#include <cstring> 
#include <unordered_set>
#include <unordered_map>
using namespace std; 

//-------------------------------------------------------Typedefs----------------------------------------------//  

typedef long long int ll; 

typedef pair<int, int> pii; 

typedef pair<ll, ll> pll; 

typedef pair<string, string> pss; 

typedef vector<int> vi; 

typedef vector<vi> vvi; 

typedef vector<pii> vii; 

typedef vector<ll> vl; 

typedef vector<vl> vvl; 

  

double EPS = 1e-9; 

int INF = 1000000005; 

long long INFF = 1000000000000000005LL; 

double PI = acos(-1); 

int dirx[8] = { -1, 0, 0, 1, -1, -1, 1, 1 }; 

int diry[8] = { 0, 1, -1, 0, -1, 1, -1, 1 }; 

//---------------------------------------------------------Hash defines--------------------------------------------------//

# define    PII     3.14159265358979323846
#ifdef TESTING 
#define DEBUG fprintf(stderr, "====TESTING====\n") 
#define VALUE(x) cerr << "The value of " << #x << " is " << x << endl 
#define debug(...) fprintf(stderr, __VA_ARGS__) 
#else 
#define DEBUG 
#define VALUE(x) 
#define debug(...) 
#endif 

  
#define FOR(a, b, c) for (int(a) = (b); (a) < (c); ++(a)) 
#define FORN(a, b, c) for (int(a) = (b); (a) <= (c); ++(a)) 
#define FORD(a, b, c) for (int(a) = (b); (a) >= (c); --(a)) 
#define FORSQ(a, b, c) for (int(a) = (b); (a) * (a) <= (c); ++(a)) 
#define FORC(a, b, c) for (char(a) = (b); (a) <= (c); ++(a)) 
#define FOREACH(a, b) for (auto&(a) : (b)) 
#define REP(i, n) FOR(i, 0, n) 
#define REPN(i, n) FORN(i, 1, n) 
#define MAX(a, b) a = max(a, b) 
#define MIN(a, b) a = min(a, b) 
#define SQR(x) ((ll)(x) * (x)) 
#define RESET(a, b) memset(a, b, sizeof(a)) 
#define ff first 
#define ss second 
#define mp make_pair 
#define pb push_back 
#define ALL(v) v.begin(), v.end() 
#define ALLA(arr, sz) arr, arr + sz 
#define SIZE(v) (int)v.size() 
#define SORT(v) sort(ALL(v)) 
#define REVERSE(v) reverse(ALL(v)) 
#define SORTA(arr, sz) sort(ALLA(arr, sz)) 
#define REVERSEA(arr, sz) reverse(ALLA(arr, sz)) 
#define PERMUTE next_permutation 
#define T(a) ll a; cin >> a;
#define TT(t) T(t); while (t--)
#define IOS ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define f(i, x, y) for(int i = x; i < y; i++)
#define array(a)   ll a[n]; 
#define line "\n";
#define out cout
#define meh <<
//-------------------------------------------------TEMPLATES----------------------------------------------------------//

	template<class T> T max(T a, T b, T c) {
	    return max(a, max(b, c));
	}
	template<class T> T min(T a, T b, T c) {
	    return min(a, min(b, c));
	}
	void SieveOfEratosthenes(ll n)//O(nloglogn)
	{
		ll prime[n];
	    memset(prime, true, sizeof(prime));
	
	    for (ll p = 2; p * p <= n; p++)
	    {
	        if (prime[p] == true)
	        {
	            for (ll i = p * p; i <= n; i += p)
	                prime[i] = false;
	        }
	    }
	}
	bool isPrime(ll n)//O(sqrt(n))
	{
	    if (n < 2)
	        return false;
	    for (ll i = 2; i * i <= n; i++)
	        if (n % i == 0)
	            return false;
	    return true;
	}
	std::vector<ll> generatePrimeFactors(ll n)
	{
	    std::vector<ll> prime;
	    for (ll i = 2; i * i <= n; i++)
	    {
	        if (n % i == 0)
	        {
	            prime.pb(i);
	            while (n % i == 0)
	                n = n / i;
	        }
	    }
	    if (n != 1)
	        prime.pb(n);
	    return prime;
	}
	std::vector<ll> generateFactors(ll n)
	{
	    std::vector<ll> fact;
	    for (ll i = 2; i * i <= n; i++)
	    {
	        if (n % i == 0)
	        {
	            fact.pb(i);
	            if (n / i != i)
	                fact.pb(n / i);
	            //24 - 1,2,3,4,6,8,12
	        }
	    }
	    fact.pb(1);
	    if (n != 1)
	        fact.pb(n);
	    sort(fact.begin(), fact.end());
	    return fact;
	}
	
	ll extendedGCD(ll a, ll b, ll &x, ll &y)
	{
	    //produces correct results for negative integers as well
	    if (a == 0)
	    {
	        x = 0;
	        y = 1;
	        return b;
	    }
	    ll x1, y1, d;
	    d = extendedGCD(b % a, a, x1, y1);
	    x = y1 - (b / a) * x1;
	    y = x1;
	    return d;
	}
	ll gcd(ll a, ll b) //O(log min(a,b))
	{
	    /*
	    recursive implementation below
	    if(!b) return a;
	    return gcd(b,a%b);
	    */
	
	    //non-recursive implementation below
	    while (b)
	    {
	        a %= b;
	        swap(a, b);
	    }
	    return a;
	}
	
	ll multiply(ll a, ll b, ll m);
	ll singlemod(ll a, ll m);
	ll modpow(ll x, ll n, ll m) //O(logn)// used for calculating (x^n)%m
	{
	    if (n == 0)
	        return 1;
	    ll res = 1;
	    while (n)
	    {
	        if (n % 2)
	            res = multiply(res, x, m);
	        x = multiply(x, x, m);
	        n = n >> 1;
	    }
	    return singlemod(res, m);
	}
	ll fastpow(ll x, ll n)
	{
	    if (n == 0)
	        return 1;
	    ll res = 1;
	    while (n)
	    {
	        if (n % 2)
	            res = res * x;
	        x = x * x;
	        n = n >> 1;
	    }
	    return res;
	}
	ll modinverse(ll x, ll m) //O(logn)
	{
	    return modpow(x, m - 2, m);
	}
	ll add(ll a, ll b, ll m)
	{
	    return (((a % m) + (b % m)) % m);
	}
	ll substract(ll a, ll b, ll m)
	{
	//    if (a < b)
	//        swap(a, b);
	    return (((a % m) - (b % m) + m) % m);
	}
	ll multiply(ll a, ll b, ll m)
	{
	    return (((a % m) * (b % m)) % m);
	}
	ll divide(ll a, ll b, ll m)
	{
	    ll temp = modinverse(b, m);
	    return multiply(a, temp, m);
	}
	bool isprime(ll n){
	for(int i = 2; i <= sqrt(n); i++){
		if(n%i == 0) 
			return false;
	}
	return true;
}
	ll singlemod(ll a, ll m)
	{
	    return (a % m);
	}
	ll eulerstotientfunction(ll n)//O(sqrt(n))
	{
	    ll ans = n;
	    for (ll i = 2; i * i <= n; i++)
	    {
	        if (n % i == 0)
	        {
	            while (n % i == 0)
	                n = n / i;
	            ans -= ans / i;
	        }
	    }
	    if (n > 1)
	        ans -= ans / n;
	    return ans;
	}
	
	ll ncr(ll n, ll k, ll m)
	{
	    if (k > n) return 0;
	    if (m == 0)
	    {
	        ll res = 1;
	        k = min(k, n - k);
	        for (ll i = 1; i <= k; i++)
	        {
	            res *= (n - i + 1);
	            res /= i;
	        }
	        return res;
	    }
	    else
	    {
	        ll res = 1;
	        k = min(k, n - k);
	        for (ll i = 1; i <= k; i++)
	        {
	            res = multiply(res, n - i + 1, m);
	            res = divide(res, i, m);
	        }
	        return singlemod(res, m);
	    }
	}
	ll kadaneAlgo(const std::vector<ll> &arr)
	{
	    ll size = arr.size();
	    ll currmax = arr[0], maxsofar = arr[0];
	    for (ll i = 1; i < size; i++)
	    {
	        //debug2(currmax,maxsofar);
	        currmax = max(arr[i], currmax + arr[i]);
	        maxsofar = max(maxsofar, currmax);
	    }
	    return maxsofar;
	}
	ll getDigitSum(ll n)
	{
	    ll co = 0;
	    while (n > 0)
	    {
	        co += n % 10;
	        n = n / 10;
	    }
	    return co;
	}
	
	template<class T>
	void printVector(const std::vector<T> arr)
	{
	    for (auto i : arr)
	        cout << i << " ";
	    cout << endl;
	}
	template<class T>
	void printArray(T arr[], ll n)
	{
	    for (ll i = 0; i < n; i++)
	        cout << arr[i] << " ";
	    cout << endl;
	}
	//const int p1 = 13331,m1 = 1e9+9,p2 = 7919, m2 = 1e9+9;
	//const int p1 = 97266353,m1 = 972663749,p2 = 97336357, m2 = 1000000007;
	//const int p1 = 31 ,m1 = 1e9+7;
	
	//grid cells
	//D U R L
	ll dx[] = {1, -1, 0, 0};
	ll dy[] = {0, 0, 1, -1};
	
	bool is_perfect(int x)
	{
	    long double y = sqrt(x);
	    return ((y - floor(y)) == 0);
	}
// this is a practice header done during Practice session --

	ll nofdigit(ll n){
		// formula used number of digits in N = log10(N) + 1 .//O(1)
		return floor(log10(n) + 1);
	}
  	ll  gp_lastterm(ll a1,ll n,ll r){
  		return a1*pow(r,n-1);
	  }
	ll  gp_sum(ll a1,ll n,ll r){
		if(r>1)
		return (a1*(pow(r,n)-1))/(r-1);
		else
		return (a1*(1-pow(r,n)))/(1-r);
	  }
	//------------------------------------------------------------------------------------------------------------
	
	  
void wiley()
{
char c;
cin>>c;
		if(c<=90&&c>=65)
		cout<<'A'<<endl;
		if(c<=122&&c>=97)
		cout<<'a'<<endl;
		
		
}

int main(){
	// Fast I/O --- Vroom Vroom 
//	IOS
////	TT(t){
	
//	read();

	wiley();
// By Order of Peaky Blinders.
//	}
	return 0;
	
}



Measured memory_bytes: 3724