#include<stdio.h>
#define MAX 100000

int parent(int i)
{
  return i/2;
}

int left(int i)
{
  return 2*i;
}

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

int main()
{

  int i,A[MAX+1],n;

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

  for(i=1;i<=n;i++)
    {
      printf("node %d: key = %d, ",i,A[i]);
      if(parent(i) >= 1) printf("parent key = %d, ",A[parent(i)]);
      if(left(i)<= n) printf("left key = %d, ",A[left(i)]);
      if(right(i) <= n) printf("right key = %d, ",A[right(i)]);
      printf("\n");
    }

  return 0;
}

