#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

typedef long long ll;

struct Node {
	ll value;

	int left;
	int right;

	Node() { }

	void set(ll value, int left, int right) {
		Node::value = value;
		Node::left = !left ? 0 : left - 1;
		Node::right = !right ? 0 : right - 1;
	}
};


bool check(vector<Node>& table, size_t i) {
	auto cur = &table[i];

	//leaf -> ok
	if (!cur->left)
		if (!cur->right)
			return true;

	// *left, 0
	// compare values, then check left son
	if (!cur->right)
		if (cur->left)
			return table[cur->left].value >= cur->value ? false : check(table, cur->left);

	// 0, *right
	// compare values, then check right son
	if (!cur->left)
		if (cur->right)
			return table[cur->right].value <= cur->value ? false : check(table, cur->right);

	// *left, *right
	// compare values, then check both
	if (table[cur->left].value >= cur->value)
		return false;
	if (table[cur->right].value <= cur->value)
		return false;
	if (!check(table, cur->left))
		return false;
	if (!check(table, cur->right))
		return false;

	// if all pass -> allright
	return true;
}

int main()
{
	ifstream ist("check.in");
	ofstream ost("check.out");

	size_t n;
	ist >> n;

	vector<Node>* table = new vector<Node>(n);

	for (size_t i = 0; i < n; i++) {
		ll value;
		int left, right;
		ist >> value >> left >> right;

		table->at(i).set(value, left, right);
	}

	ost << (n == 0 ? "YES" : (check(*table, 0) ? "YES" : "NO"));

	return 0;
}