#include<stdio.h>

int parent(int i){return i/2;}
int left(int i){return 2*i;}
int right(int i){return 2*i+1;}

int main(){
    int H, i, A[1000];

    scanf("%d", &H);
    for(i=1; i<=H; i++){
        scanf("%d", &A[i]);
    }

    for(i=1; i<=H; i++){
        printf("node %d: key = %d, ", i, A[i]);
        if(parent(i)>=1) printf("parent key = %d, ", A[parent(i)]);
        if(left(i)<=H) printf("left key = %d, ", A[left(i)]);
        if(right(i)<=H) printf("right key = %d, ", A[right(i)]);
        printf("\n");
    }

    return 0;
}
