#include <stdio.h>

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

  scanf("%d",&n);

  for(i=0;i<n;i++)
    {
      scanf("%d",&H[i]);
    }

  for(i=1;i<n+1;i++)
    {
      printf("node %d: key = %d, ",i,H[i-1]);

      if(i/2 >= 1) printf("parent key = %d, ",H[i/2-1]);
      if(i*2 <= n) printf("left key = %d, ",H[i*2-1]);
      if(i*2+1 <= n) printf("right key = %d,",H[i*2]);

      printf("\n");
    }

  return 0;
}
	