#include <bits/stdc++.h>
using namespace std;

int main()
{
	int N, M;
	cin >> N >> M;
	vector<long long> T( M );
	vector<int> P( M );
	for( int i = 0; i < M; i++ ) {
		cin >> T[i] >> P[i];
	}

	long long ct = 0;
	long long cp = 0;
	string ans = "Yes";
	for( int i = 0; i < M; i++ ) {
		if( abs(P[i] - cp) > T[i] - ct ) {
			ans = "No";
			break;
		}
		ct = T[i];
		cp = P[i];
	}

	cout << ans << endl;
}