/* Complete Binary Tree */
#include <stdio.h>
#define MAX 250

int main()
{
    int n, i, a[MAX];

    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+1, a[i]);

        if(i){
            printf("parent key = %d, ", a[(i+1)/2-1]);
        }
        if(2*i+1 < n){
            printf("left key = %d, ", a[2*i+1]);
        }
        if(2*i+2 < n){
            printf("right key = %d, ", a[2*i+2]);
        }
        printf("\n");
    }
    return 0;
}
