#include <iostream>
#include <algorithm>
using namespace std;
int main() {
	int N;
	int K_score = 0;
	int a[100];
	int b[100];
	int score[100] = { 0 };
	cin >> N;
	for (int i = 0; i < N;i++) {
		cin >> a[i] >> b[i];
		if (b[i] == 0) {
			K_score += a[i];
		}
		else {
			score[b[i] - 1] += a[i];
		}
	}
	sort(b, b + 100);
	if (K_score >= b[99]) { cout << "YES" << endl; }
	else {
		cout << "NO" << endl;
	}
	return 0;
}