# 目次

• 目次
• 解答

# 解答

// C++ 14
#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <algorithm>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <unordered_map>
#include <math.h>

#define ll long long
#define Int int
#define loop(x, start, end) for(Int x = start; x < end; x++)
#define loopdown(x, start, end) for(int x = start; x > end; x--)
#define rep(n) for(int x = 0; x < n; x++)
#define span(a,x,y) a.begin()+x,a.begin()+y
#define span_all(a) a.begin(),a.end()
#define len(x) (x.size())
#define last(x) (*(x.end()-1))

using namespace std;

#define MAX 100000

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

int main(void){
    int H, i, A[MAX+1];
    
    cin >> H;
    for (int i=0; i<=H; i++) {
        cin >> A[i];
    }
    
    for (int i=0; i<=H; i++) {
        cout << "node " << i << ": key = " << A[i] << ", ";
        if (parent(i) >= 1) cout << "parent key = " << A[parent(i)] << ", ";
        if (left(i) <= H) cout << "left key = " << A[left(i)] << ", ";
        if (right(i) <= H) cout << "right key = " << A[right(i)] << ", ";
        cout << endl;
    }
    
    return 0;
}