#include <stdio.h>

#define NMAX 1000001

int parent(int i){
  return i/2;
}

int left(int i){
  return i * 2;
}

int right(int i){
  return i * 2 + 1;
}

int main(void){
  int H,i,A[NMAX];

  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;   
}

