#define _USE_MATH_DEFINES

#include <iostream>	//cin, cout
#include <vector>	//vector
#include <algorithm> //sort,min,max,count
#include <string>	//string,getline, to_string
#include <ios>		//fixed
#include <iomanip>	//setprecision
#include <utility> //swap, pair
#include <cstdlib>	//abs(int)
#include <cmath>	//sqrt,ceil,M_PI, pow, sin
#include <sstream>	//stringstream,getline
#include <numeric>	//gcd, accumlate
#include <deque>	//deque
#include <random>	//randam_device
#include <limits>	//numeric_limits

using namespace std;
constexpr long long int D_MOD = 1000000007;

int main() {

	int N, M;
	cin >> N >> M;
	
	bool flg = true;
	long long int nowT = 0, nowP = 0;

	for (int i = 0; i < M; i++) {
		long long int T, P;
		cin >> T >> P;

		if (T - nowT >= abs(P - nowP)) {
			nowT = T;
			nowP = P;
		}
		else {
			flg = false;
			break;
		}
	}

	if (flg) { cout << "Yes" << endl; }
	else { cout << "No" << endl; }

	return 0;

}