using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("enter marks");

        int a = Int32.Parse(Console.ReadLine());

        bool r1 = a > 80;

        switch (r1)

        {

            case true:

                Console.WriteLine("A");

                break;

            case false:

                Console.WriteLine("B");

                break;  

        }

    }

}