#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 n, i, a[MAX+1];

  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;
}