using System;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var a = Enumerable.Range (1,3);

        var b = Enumerable.Range (4,3);

        var res = a.SelectMany ( x => b, (c,d) => new {c,d});

        foreach (var r in res) 

            Console.WriteLine (r);

    }

}