using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
public class Program
{
public static void Main()
string [] list1 = {"1", "2", "3", "4", "3"};
string [] list2 = {"9", "3", "8"};
var xx = list1.Where(x=>list2.Contains(x)).Distinct();
foreach(var x in xx){
Console.WriteLine(x);
}