using System;
public class Program
{
private static string ReverseCase(string str)
return str;
}
public static void Main()
Console.WriteLine(ReverseCase("Happy Birthday")); //"hAPPY bIRTHDAY"
Console.WriteLine(ReverseCase("MANY THANKS")); //"many thanks"
Console.WriteLine(ReverseCase("sPoNtAnEoUs")); //"SpOnTaNeOuS"