#include <stdio.h>

#define MAX_H 251

int parent(int );
int left(int );
int right(int );


int main(){
  int H=0;
  int A[MAX_H];
  int i=0;

  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)!=0)printf("parent key = %d, ",A[i/2]);
    if(left(i)<=H)printf("left key = %d, ",A[2*i]);
    if(right(i)<=H)printf("right key = %d, ",A[2*i+1]);
    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;
}

