#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 i*2+1;
}



int main(){

  int H=0,i,A[MAX+1];

  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;
}

