#include <iostream>
#include <cmath>
using namespace std;

long long N, M;
long long T[1 << 19], P[1 << 19];

int main() {
	cin >> N >> M;
	for (int i = 1; i <= M; i++) cin >> T[i] >> P[i];
	for (int i = 1; i <= M; i++) {
		long long dst = abs(P[i - 1] - P[i]);
		if (dst > T[i] - T[i - 1]) {
			cout << "No" << endl;
			return 0;
		}
	}
	cout << "Yes" << endl;
	return 0;
}