Problem:
Score : 100 points

Problem Statement

An uppercase or lowercase English letter \alpha will be given as input.
If \alpha is uppercase, print A; if it is lowercase, print a.

Constraints

\alpha is an uppercase (A - Z) or lowercase (a - z) English letter.

Input

Input is given from Standard Input in the following format:

α

Output

If \alpha is uppercase, print A; if it is lowercase, print a.

Sample Input 1

B

Sample Output 1

A

B is uppercase, so we should print A.

Sample Input 2

a

Sample Output 2

a

a is lowercase, so we should print a.

Solution in C# (.NET Core 3.1.201) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace AtCoder.Abc
{
    /// <summary>
    /// https://atcoder.jp/contests/abc172/tasks/abc172_b
    /// </summary>
    class A_171_αlphabet
    {
        public static void Main(string[] args)
        {
            var sw = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);

            // 文字列の入力
            string a = Console.ReadLine();

            if (Regex.IsMatch(a, "[A-Z]"))
            {
                a = "A";
            }
            else
            {
                a = "a";
            }



            string result = a;

            Console.WriteLine(result);

            Console.Out.Flush();
        }
    }
}