#include <stdio.h>
#include <stdlib.h>

void find_duplicates(int ids[], int n) {
    int count[RANGE] = {0};
    int duplicates[MAX_IDS];
    int duplicates_count = 0;
    
    for (int i = 0; i < n; i++) {
      count[ids[i] + 1000]++;
    }
    for (int i = 0; i < RANGE; i++) {
        if (count[i] > 1) {
            duplicates[duplicate_count++] = i - 1000;
        }
    }
    if (duplicate_count == 0) {
        printf("No duplicates found\n")
    } else {
        for (int i = 0; i < duplicate_count; i++) {
            printf(i < duplicate_count - 1) {
                printf(" ");
            }
        }
        printf("\n");
    }
}
int main() {
    int n;
    if (scanf("%d", &n) !=1) {
        return 1;
    }
    if (n < 1) {
        printf("Invalid input\n"); 
    } else if(n > 100)  {
        int ids[MAX_IDS];
        for (int i = 0; i < n; i++) {
           if (scnaf("%d", &ids[i]) != 1)  {
               return 1;
        }
    }
    find_duplicates(ids, n);
} else {
    int ids[MAX_IDS];
    for (int i =0; i < n; i++) {
        if (scanf("%d", &ids[i]) != 1) {
            return 1;
        }
    }
    find_duplicates(ids, n);
}
return 0;
}