#define _USE_MATH_DEFINES

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

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


int main() {

    int N, M, T, P;
    cin >> N >> M;

    int nowP = 0;
    int nowT = 0;

    for (int i = 0; i < M; i++) {
        cin >> T >> P;
        if (T - nowT < abs(P - nowP)) {
            cout << "No" << endl;
            return 0;
        }
        else {
            nowT = T;
            nowP = P;
        }
    }

    cout << "Yes" << endl;

    return 0;

}