#include <stdio.h>
#define MAX 1000000


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;
  int A[MAX+1];
  int 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");
  }
  for( i= 1; i< n; i++);
  
  return 0;
    
}

