#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n, m;
    cin >> n >> m;
    vector<long long> a(m + 1), b(m + 1);
    a[0] = 0, b[0] = 0;
    for (int i = 1; i <= m; ++i) {
        cin >> a[i] >> b[i];
        if (a[i] - a[i - 1] < abs(b[i] - b[i - 1])) {
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
}