#include <bits/stdc++.h>

using namespace std;

const int mMax = 100010;
int T[mMax], P[mMax];

int main() {
    int N, M;
    cin >> N >> M;
    for (int i = 1; i <= M; ++i) {
        cin >> T[i] >> P[i];
    }

    int curT = 0, curP = 0;
    for (int i = 1; i <= M; ++i) {
        if (abs(curT - T[i]) < abs(curP - P[i])) {
            cout << "No" << endl;
            return 0;
        } else {
            curT = T[i], curP = P[i];
        }
    }

    cout << "Yes" << endl;
    return 0;
}