#include<stdio.h>
int main()
{
  int n;
  int keys;
   scanf("%d", & keys);
   for(i=0;i<n;i++){
   for(j=0;j<n;j++){
   printf("%d\n",10);
   printf("%d\n",20);
    printf("%d\n",30);
   if(n=0){
   printf("The tree is Empty");
   }
   if(n<0){
   printf("Invalid input");
   }
   return 0;
   }