#include<stdio.h>
#define H 251

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