// #define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
int main() {
    // Input
    int N, M;
    cin >> N >> M;
    vector<long long> T(M + 1);
    vector<int> P(M + 1);
    rep(i, M) cin >> T[i + 1] >> P[i + 1];

    // Judge
    bool ok = true;
    rep(i, M) if (abs(T[i + 1] - T[i]) < abs(P[i + 1] - P[i])) ok = false;

    // Output
    cout << (ok ? "Yes" : "No") << endl;
}