#include<stdio.h>

int parent(int);

int left(int);

int right(int);


int main(){
  int h,i,j,a[251];

  scanf("%d",&h);

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

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

    if(parent(i)>=1) printf("parent key = %d, ",a[parent(i)]);

    if(left(i)<=h) printf("left key = %d, ",a[left(i)]);

    if(right(i)<=h) 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;
}

