#include<stdio.h>
int main()
{
    int N;
    int found = 0;
    scanf("%d",&N);
    if(N<0)
    {
        printf("Invalid input");
        return 0;
    }
    int arr[N];
    for(int i=0;i<N;i++)
    {
        scanf("%d",&arr[i]);
    }
    for(int i=0;i<N;i++)
{
        for(int j=j+1;j<N;j++)
        {
        if(arr[i]==arr[j])
        {
        printf("%d",arr[i]);
        found=1;
        break;
    }
        }
    if(!found){
        printf("no duplicates found");
    }
}