#include<stdio.h>
#define N 1000
main(){
  int n, i;
  int A[N];

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

  for (i = 1; i <= n; i++) {
    printf("node %d: key = %d, ",i,A[i]);
    if( i/2 != 0 )printf("parent key = %d, ",A[i/2]);
    if( 2*i <= n ) printf("left key = %d, ",A[2*i]);
    if( 2*i+1 <= n ) printf("right key = %d, ",A[2*i+1]);
    printf("\n");
  } 
  return 0;
}