#include<stdio.h>
int main(){
    int n;
    scanf("%d",&n);
    if(n<1){
    printf("Invalid Input\n");
    return 0;
}
    int duplicates;
    scanf("%d",&duplicates);
    for(int i=0;i<n;i++){
        int ids;
        scanf("%d",&ids);
        if(ids[id+1000]>1 && ids[id+1000]<=1){
           duplicates[duplicatescount++]=ids;
        }
    }
    if(duplicatescount==0){
        printf("No duplicates found\n");
    }
    else{
        for(int i=0;i<duplicatescount;i++){
            printf("%d",duplicates[i]);
        }
        printf("\n");
    }
    
    return 0;
}