#include<stdio.h>

int parent(int);
int right(int);
int left(int);

#define MAX 100000

int main()
{
  int i,kazu,A[MAX+1];

  scanf("%d",&kazu);

  for(i=1;i<=kazu;i++)
    scanf("%d",&A[i]);

  for(i=1;i<=kazu;i++)
    {
      printf("node %d: key = %d, ",i,A[i]);

      if(parent(i)>=1) printf("parent key = %d, ",A[parent(i)]);
      if(left(i)<=kazu) printf("left key = %d, ",A[left(i)]);
      if(right(i)<=kazu) printf("right key = %d, ",A[right(i)]);

      printf("\n");
    }

  return 0;
}


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

