#include <bits/stdc++.h>

using namespace std;

using ll = long long;

constexpr char newl = '\n';

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n, m;
    cin >> n >> m;

    ll ct = 0;
    int cp = 0;
    bool ans = true;
    for (int i = 0; i < m; i++) {
        ll t;
        int p;
        cin >> t >> p;
        if (t - ct < abs(p - cp)) {
            ans = false;
            break;
        }
        ct = t;
        cp = p;
    }
    cout << (ans ? "Yes" : "No") << newl;

    return 0;
}