#include<stdio.h>
int main()
{
    int n;
    scanf("%d",&n);
    if(n<=1)
    {
        printf("invalid input\n");
        return 0;
    }
    int ids[n],dup[100],dcount=0;
    for (int i=0;i<n;i++){
    for(int j=i+1;j<n;j++)
    {
        if(ids[i]==ids[j])
        {
        int already =0;
        for (int k=0;k<dcount;k++){
            if(dup[k]==ids[i]){
                already=1;
                break;
                
            }
        }
    }
    }
}