  #include<stdio.h>
  #define MAX 100000

  int parent(int);
  int left(int);
  int right(int);

  int main(){
    int H,i,A[MAX+1];

    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(left(i)<=H)printf("left key = %d, ",A[left(i)]);
      if(right(i)<=H)printf("right key = %d, ",A[right(i)]);
      printf("\n");
    }
    return 0;
  }

  int parent(int i){return i/2;}
  int left(int i){return i*2;}
  int right(int i){return i*2+1;}