#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int N,M; cin >> N >> M;
    vector<pair<ll,ll>> TP;
    TP.push_back({0, 0});
    rep(i,M) {
        int t,p; cin >> t >> p;
        TP.push_back({t, p});
    }

    int ok = 1;
    rep(i,M) {
        ll dt = TP[i + 1].first - TP[i].first;
        ll dp = TP[i + 1].second - TP[i].second;
        ok &= dp <= dt;
    }

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