#include <stdio.h>
#define MAX 100000

int parent(int);
int left(int);
int right(int);

int main(){
    int n,i;
    int A[MAX+1];
    scanf("%d",&n);
    for(i=1;i<=n;i++) scanf("%d",&A[i]);
    for(i=1;i<=n;i++){
        printf("node %d: key = %d, ",i,A[i]);
        if(parent(i)>=1) printf("parent key = %d, ",A[parent(i)]);
        if(left(i)<=n) printf("left key = %d, ",A[left(i)]);
        if(right(i)<=n) printf("right key = %d, ",A[right(i)]);
        printf("\n");
    }
    return 0;
}
int parent(int i){
    return i/2;
}
int left(int i){
    return i*2;
}
int right(int i){
    return i*2+1;
}
