/*
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       ,"   __,'            \         \--""""""==;-
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             ,':::::::::::||::::::::::::'.
    .__     ;:::.-.:::::__||___:::::.-.:::\     __,
       """-;:::( O )::::>_|| _<::::( O )::::-"""
   =======;:::::`-`:::::::||':::::::`-`:::::\=======
    ,--"";:::_____________||______________::::""----.          , ,
         ; ::`._(    |    |||     |   )_,'::::\_,,,,,,,,,,____/,'_,
       ,;    :::`--._|____[]|_____|_.-'::::::::::::::::::::::::);_
      ;/ /      :::::::::,||,:::::::::::::::::::::::::::::::::::/
     /; ``''''----------/,'/,__,,,,,____:::::::::::::::::::::,"
     ;/                :);/|_;| ,--.. . ```-.:::::::::::::_,"
    /;                :::):__,'//""\\. ,--.. \:::,:::::_,"
   ;/              :::::/ . . . . . . //""\\. \::":__,"
   ;/          :::::::,' . . . . . . . . . . .:`::\
   ';      :::::::__,'. ,--.. . .,--. . . . . .:`::`
   ';   __,..--'''-. . //""\\. .//""\\ . ,--.. :`:::`
   ;    /  \\ .//""\\ . . . . . . . . . //""\\. :`::`
   ;   /       . . . . . . . . . . . . . . . . .:`::`
   ;   (          . . . . . . . . . . . . . . . ;:::`
   ,:  ;,            . . . . . . . . . . . . . ;':::`
   ,:  ;,             . . . . . . . . . . . . .;`:::
   ,:   ;,             . . . . . . . . . . . . ;`::;`
    ,:  ;             . . . . . . . . . . . . ;':::;`
     :   ;             . . . . . . . . . . . ,':::;
      :   '.          . . . . . . . .. . . .,':::;`
       :    `.       . . . . . . . . . . . ;::::;`
        '.    `-.   . . . . . . . . . . ,-'::::;
          `:_    ``--..___________..--'':::::;'`
             `._::,.:,.:,:_ctr_:,:,.::,.:_;'`
________________`"\/"\/\/'""""`\/"\/""\/"____________________________
*/
#include <bits/stdc++.h>
using namespace std;

#define FASTIO ios_base::sync_with_stdio(false); cin.tie(nullptr)

using ll = long long int;
using pii = pair<int, int>;
using pid = pair<int, double>;
using pLL = pair<ll, ll>;
using pll = pair<long int, long int>;
using pis = pair<int, string>;
using vL = vector<ll>;
using vi = vector<int>;
using vs = vector<string>;

#define ff first
#define ss second
#define pb push_back
#define loope(i, n) for (int i = 1; i <= n; i++)
#define loop(i, n) for (int i = 0; i < n; i++)
#define kaj_sesh return 0
#define ferot_ja return
const double pi = acos(-1);


//debugger
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}


#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
//debugger


bool comp(const pid &a,const pid &b)
{
    return (a.ss > b.ss) or (a.ss==b.ss && a.ff < b.ff);
}

void solve()
{
  char x;
  cin>>x;
  if(x>='a' && x<='z') printf("a\n");
  else printf("A\n");
   
}

signed main()
{
 

  /*int ts;
    cin >> ts;
    while(ts--) */
  solve();
  kaj_sesh;
}

Measured memory_bytes: 3620