#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;

typedef long long ll;

int main() {
    int N, M;
    cin >> N >> M;
    vector<pair<ll, int>> TP(M);
    rep(i, M) {
        cin >> TP[i].first >> TP[i].second;
    }
    ll t = 0, p = 0;
    rep(i, M) {
        if (abs(TP[i].second - p) > TP[i].first - t) {
            cout << "No\n";
            return 0;
        }
        t = TP[i].first;
        p = TP[i].second;
    }
    cout << "Yes\n";
}