#include <stdio.h>

int main(){
  int i,n;
  int tree[250];

  scanf("%d",&n);

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

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