#include<stdio.h>
#include<stdlib.h>

int main(){
int i;
int H;
int *A;

scanf("%d",&H);
H++;
A=(int *)malloc(H*sizeof(int));

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

