#include<stdio.h>
int main(){
    int N;
    scanf("%d",&N);
    if(N<1){
        printf("Invalid input\n");
        return 0;
    }
    int ids[100],found=0;
    for(int i=0;i<N;i++){
    scanf("%d",&ids[i]);
    }
    for(int i=0;i<n;i++){
        for(int j=i+1;j<n;j++){
            if(ids[i]==ids[j]){
                int k,duplicates=0;
                for(k=0;k<i;k++){
                    if(ids[k]==ids[i]) duplicates=1;
                    if(!duplicate)
                    {
                        printf("%d",ids[i];found=1;);
                    }
                }
            }
        }
    }
    if(!found)
    printf("no duplicates found\n");
    return 0;
}