using System;
using System.Collections.Generic;
using System.Linq;

public class Test
{
	public static void Main()
	{
            List<string> A_list = new List<string>() { "one", "two", "three" };
            List<string> B_list = new List<string>() { "two", "three", "four" };
            var newlist = A_list.Intersect(B_list); 

            foreach (var i in newlist)
                Console.WriteLine(i);
	}
}