public static void Main()
texto = Console.ReadLine();
dia = int.Parse(texto.Split('/')[0]);
mes = int.Parse(texto.Split('/')[1]);
ano = int.Parse(texto.Split('/')[2]);
DateTime date = new DateTime(ano, mes, dia);
Console.WriteLine(date.ToString("MM/dd/yy"));
Console.WriteLine(date.ToString("yy/MM/dd"));
Console.WriteLine(date.ToString("dd-MM-yy"));