#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 2*i+1;
}

int main(){
  int H, 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;
}

