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.Numerics;

class Program {
    static void Main (string[] args) {
        var input = INP();
        char ch = input[0][0];
        if(Char.IsUpper(ch)) {
            CWL("A");
        } else {
            CWL("a");
        }
    }

    public static List<int> PrimeFactors (int n) {
        var tmpList = new List<int>();
        int i = 2;
        int tmp = n;

        while(i * i <= n) {
            if(tmp % i == 0) {
                tmp /= i;
                tmpList.Add(i);
            } else {
                i++;
            }
        }

        if(tmp != 1) tmpList.Add(tmp);

        return tmpList;
    }

    static string[] INP () {
        return Console.ReadLine().Split(' ');
    }

    static void CWL (string value) {
        Console.WriteLine(value);
    }

    static void CWL (int value) {
        Console.WriteLine(value);
    }

    static void CWL (long value) {
        Console.WriteLine(value);
    }

    static void CWL (float value) {
        Console.WriteLine(value);
    }

    static void CWL (double value) {
        Console.WriteLine(value);
    }

    static int TOI (string str) {
        return int.Parse(str);
    }

    static long TOL (string str) {
        return long.Parse(str);
    }

    static float TOF (string str) {
        return float.Parse(str);
    }

    static double TOD (string str) {
        return double.Parse(str);
    }

    /*static void Main (string[] args) {
        var input = INP();
        var input2 = INP();
        var input3 = INP();

        CWL("dummy");
    }*/
}