#include <stdio.h>
 
 
int main(){
     
  int n,i,size[1000];
    
  scanf("%d",&n);
    
  for (i = 1; i <= n; i++) {
        scanf("%d",&size[i]);
    }
 
 
    for(i = 1; i < n; i++){
        printf("node %d: key = %d, ",i,size[i]);
         
        if(i != 1){
            printf("parent key = %d, ",size[i/2]);
        }
        if(2*i < n){
            printf("left key = %d, ",size[2*i]);
        }
        if(2*i + 1 < n) {
            printf("right key = %d, ",size[2*i+1]);
        }
        printf("\n");
    }
    return 0;
}