#include <stdio.h>

#define MAX 10000

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 A[MAX+1],H,i;

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

  for(i=1;i<=H;i++){
    printf("node %d: ",i);
    printf("key = %d, ",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;
}





