#include <stdio.h>
#define MAX 10000

int parent(int i) {return i/2;}
int R(int i) {return 2*i+1;}
int L(int i) {return 2*i;}

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

  scanf("%d",&H);

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

  for(i=1;i<=H;i++){
    printf("node %d: key = %d, ",i,A[i]);
    if(parent(i)>=1) printf("parent key = %d, ",A[parent(i)]);
    if(L(i)<=H) printf("left key = %d, ",A[L(i)]);
    if(R(i)<=H) printf("right key = %d, ",A[R(i)]);
    printf("\n");
  }

  return 0;
}

