using System;

public class Program

{

    public static void Main()

    {

        Console.Write("请输入：");

        char c=char.Parse(Console.ReadLine());

        if(c>='a'&&c<='z')

            Console.WriteLine("小写字母{0}转为大写字母{1}",c,Convert.ToChar(c+32));

        else if(c>='A'&&c<='Z')

            Console.WriteLine("大写字母{0}转为小写字母{1}",c,Convert.ToChar(c-32));

        else

            Console.WriteLine("{0}不是字母，不作处理",c);

        Console.ReadLine();

    }

}