import java.util.*;

public class Main {
    public static void main(String[] args) {
      Integer arr[]={1,2,3,4,5,6};
      Integer arr1[]={1,3,7,8};
      Set<Integer> obj  = new LinkedHashSet<>();
      for(int i=0;i<arr.length;i++){
       obj.add(arr[i]);
      }
      for(int i=0;i<arr1.length;i++){
      if (obj.contains(arr1[i])){
     System.out.print(arr1[i]+",");
   }
  }
 }
}