#include <stdio.h>

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

  scanf("%d",&n);

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

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

  return 0;
}
   

      