#include <stdio.h>
#define MAX 250

int main(){

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