#include <stdio.h>
int main(){
  int n,i;
  int a[1000];
 
  scanf("%d",&n);
  
  for(i=0;i<n;i++) scanf("%d",&a[i]);
  
  for(i=0;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;
}