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: Runtime Error)

using System;
using System.Linq;

namespace Sample
{
    class Sample
    {
        static void Main(string[] args)
        {
            var n = long.Parse(Console.ReadLine());
            string res = FindAlpfa(n);
            Console.WriteLine(res);
        }

        private static string FindAlpfa(long n)
        {
            long thischar = 0;
            if (n % 26 == 0)
                thischar = 26;
            else
                thischar = n % 26;

            if (n == thischar)
                return ((char)(thischar + 96)).ToString();

            return FindAlpfa((n - thischar) / 26) + ((char)(thischar + 96)).ToString();
        }
    }

}