#include <stdio.h>
int main(){
  int n,i;
  int a[1000];

  scanf("%d",&n);
  for(i=0;i<n;i++){
    scanf("%d",&a[i]);
  }
  for(i=0;i<n;i++){
    printf("node %d: key = %d, ",i,a[i]);
    if( i/2 != 0 ){
      printf("parent key = %d, ",a[i/2]);
    }
    if(2*i <=n){
      printf("left key = %d, ",a[i*2]);
    }
   if( 2*i+1 <= n ) {
      printf("right key = %d, ",a[2*i+1]);
    }

    printf("\n");
}
return 0;
}