using System;

public class Program

{

    public class Solution {

        public int[] CommonElems(int[] a1, int[] a2) {

            int leftIndex=0;

            int rightIndex=0;

            int left=0;

            int right=0;

            int[] output = new int[a1.Length];

            int outputIndex=0;

            while (leftIndex < a1.Length || rightIndex < a2.Length) {

                left=a1[leftIndex];

                right=a2[rightIndex];

                if (left==right) {

                    output[outputIndex]= left;

                    outputIndex++;

                }

                else if (right > left) {

                    leftIndex++;

                }

                else {

                    rightIndex++;

                }

            }

            return output;

        }

    }

    public static void Main()

    {

        Console.WriteLine("Hello World");

        int[] a1=new int[]{1,2,3,4,5,6,7,8};

        int[] a2=new int[]{2,4,6,8,9,11,12,22};

        var output=new Solution().CommonElems(a1, a2);

        Console.WriteLine(output.Length);

    }

}