#include <stdio.h>
#include <stdlib.h>
#define MAX 100000
  
typedef struct node * Node;
#define NIL NULL
 
int main(){
    int i,j,n;
    int A[MAX+1];
    scanf("%d",&n);
    for(i=1; i<n+1; i++){
        scanf("%d",&A[i]);
    }
    for(i=1;i<n+1;i++){
        printf("node %d: key = %d, ",i,A[i]);
        if(i>1)printf("parent key = %d, ",A[i/2]);
        if(i*2<n+1)printf("left key = %d, ",A[i*2]);
        if(i*2+1<n+1)printf("right key = %d, ",A[i*2+1]);
        printf("\n");
    }
}
