#include <stdio.h>

int main(){

  int i,n,H[250];
  scanf("%d",&n);

  for(i=1;i<=n;i++)scanf("%d",&H[i]);
  i=1;
    printf("node %d: key = %d,left key = %d, right key = %d,\n",i,H[i],H[i*2],H[i*2+1]);
    
  for(i=2;i<=n;i++){
    
    printf("node %d: key = %d,",i,H[i]);

      if(H[i/2]!=NULL)printf("parent key = %d,",H[i/2]);
      
      if(i*2<=n)printf("left key = %d,",H[i*2]);

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

      printf("\n");
}

  return 0;
}

