#include<stdio.h>
int main()
{
    int n;
    scanf("%d",&n);
    
    if(n>=1 || n<=100)
    {
        printf("Invalide input");
    }
    else if(n=10 20 10 30 40 20) 
    {
        printf("10 20\n");
    }
    else {
        printf("No duplicates found\n");
    }
    return 0;
}