#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>
#include <bitset>
#include <cassert>

using namespace std;


int main() {

    long N, M;
    cin >> N >> M;
    long p0 = 0;
    long t0 = 0;
    bool ok = true;
    for (long i = 0; i < M; ++i) {
        long T, P;
        cin >> T >> P;

        if ((P - p0) > (T - t0)) {
            ok = false;
            break;
        }

        t0 = T;
        p0 = P;
    }

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


    return 0;

}