#include <bits/stdc++.h>
#define rep(a,n) for (int a = 0; a < (n); ++a)
using namespace std;
using ll = long long;
typedef pair<ll,ll> P;
typedef pair<P,ll> PP;
typedef vector<vector<ll> > Graph;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const ll INF = 1e18;

int main(){
    ll n,m;
    cin >> n >> m;
    vector<P>que;
    que.push_back({0,0});
    rep(i,m){
        ll t,p;
        cin >>  t >> p;
        que.push_back({t,p});
    }
    bool ans = true;
    rep(i,m){
        ll t_diff =que[i+1].first-que[i].first;
        ll p_diff = abs(que[i+1].second-que[i].second);
        if(t_diff<p_diff)ans=false;
    }
    if(ans){
        cout << "Yes" << endl;
    }
    else{
        cout << "No" << endl;
    }
    return 0;
}