#include <iostream>
#include <map>
using namespace std;
 
 
int main() {
	int s, n, ds, db, it;
	map<int, int>dragons;
	cin >> s >> n;
	for (int i = 0; i < n; i++) {
		cin >> ds >> db;
		dragons.insert(pair<int, int>(ds, db));
	}
	for (int j = 0; j < n; j++) {
		it = dragons.begin()->first;
		if (s > it) {
			s += dragons.begin()->second;
			dragons.erase(dragons.begin());
		}
		else {
			cout << "NO";
			return 0;
		}
	}
    cout << "YES";
	return 0;
}

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