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

  scanf("%d",&n);
  for(i=0;i<=n;i++) {
    scanf("&d",&A[i]);
  }

  for(i=0;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)<=1) printf("right key = %d, ",A[right(i)]);

    printf("\n");
  }

  return 0;