#include<bits/stdc++.h>
using namespace std;
#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
#define vec vector<ll>
#define mat vector<vector<ll> >
#define fi first
#define se second
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
typedef long double ld;
typedef complex<double> comp;
const ll inf=1e9+7;
const ll mod=1e9+7;
const int MAX=300010;

vector<long long> mindiv(MAX);
void osa_k(){
    mindiv[1]=1;
    for(long long i=2;i<=MAX;i++){
        if(mindiv[i]>0)continue;
        long long k=1;
        while(k*i<MAX){
            if(mindiv[k*i]==0)mindiv[i*k]=i;
            k++;
        }
    }
}

signed main(){
    ll n,m;cin>>n>>m;
    bool f=1;
    ll now=0;
    ll la=0;
    rep(i,m){
        ll t,p;cin>>t>>p;
        if(abs(p-now)>t-la)f=0;
        la=t;
        now=p;
    }
    if(f){
        cout<<"Yes"<<endl;
    }else{
        cout<<"No"<<endl;
    }
}