#include <stdio.h>
#define MAX 100000

int parent(int i){return i/2;};
int left(int i){return i*2;};
int right(int i){return i*2+1;};

int main()
{
  int H,i,A[MAX];
  
  scanf("%d",&H);
  for(i = 1; i < H; i++)
    scanf("%d",&A[i]);
  for(i = 1;i < H; i++)
    {
      printf("node %d: key = %d, ",i+1,A[i]);
      if(parent(i) >= 1) printf("parent key = %d, ",A[parent(i)]);
      if(left(i) <= H) printf("left key = %d, ",A[left(i)]);
      if(right(i) <= H) printf("right key = %d, ",A[right(i)]);
      printf("\n");
    }
  
  return 0;
}
