using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var arr1 = new [] {1, 2, 3, 4, 5, 6, 7, 8, 9};

        var arr2 = new [] {1, 5, 9};

        FindData(arr1, arr2);

    }

    private static void FindData(int[] arr1, int[] arr2)

    {

        var result = new List<int>();

        foreach(var item in arr1)

        {

            foreach(var it in arr2)

            {

                if(item == it)

                {

                    result.Add(it);

                    Console.WriteLine(it);

                }

            }

        }       

    }

}