#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( A[parent(i)] != 0  ) printf("parent key = %d, ", A[parent(i)]);
    if( A[left(i)] != 0 ) printf("left key = %d, ", A[left(i)]);
    if( A[right(i)] != 0 ) printf("right key = %d, ", A[right(i)]);
    printf("\n");
  }
  return 0;
}

