public class Program
{
    public static void Main()
    {
        string s = "OsChInAhI§$%&/()1234567890";
        Func<char, char> toggle = c => char.IsUpper(c) ? char.ToLower(c) : char.ToUpper(c);
        Console.WriteLine(s);
        Console.WriteLine(new string(s.Select(toggle).ToArray()));
    }
}