using System;

public class Program

{

    public static void Main()

    {

        var rnd = new Random();

        var rnd3 = rnd.Next(900, 1000); // 900 <= x < 1000 

        var rnd2 = rnd.Next(70, 89); // 70 <= x < 89

        var rnd4 = rnd.Next(0, 10000); // 0 <= x < 10000

        var itin = rnd3 + "-" + rnd2 + "-" + rnd4.ToString("0000");

        Console.WriteLine(itin);

    }

}