import java.util.Scanner;
class Main
{
    public static void main(String[] args)
    {
        Scanner s=new Scanner(System.in);
        int n=s.nextInt();
        if(!s.hasnextInt())
        {
            System.out.println("Invalid input");
            return;
        }
        int arr[]=new int[n];
        if(n<0)
        {
            System.out.println("Invalid input");
        }
        for(int i=0;i<n;i++)
        {
            arr[i]=s.nextInt();
        }
        boolean found=false;
        for(int i=0;i<n;i++)
        {
            for(int j=i+1;j<n;j++)
            {
                if(arr[i]==arr[j])
                {
                    found=true;
                    System.out.println(+arr[i]);
                    break;
                }
            }
        }
        if(!found)
        {
            System.out.println("No duplicates found");
        }
    }
}