#include <bits/stdc++.h>

using namespace std;

int main() {
    int n, m;
    cin >> n >> m;
    int tnow = 0;
    int pnow = 0;
    for (int i = 0; i < m; i++) {
        int t, p;
        cin >> t >> p;
        if (t - tnow >= abs(p - pnow)) {
            tnow = t;
            pnow = p;
        } else {
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
    return 0;
}