#include <stdio.h>

#define MAX 251

static int parent(int i)
{
    return i / 2;
}

static int left(int i)
{
    return 2 * i;
}

static int right(int i)
{
    return 2 * i + 1;
}

int main()
{
    int H;
    int A[MAX];

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

    for (int 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");
    }
}
