#include <iostream>
#include <utility>
#include <vector>
#include <string>
#include <cstdio>


using namespace std;

int main(){

    int n,m;
    cin>>n>>m;
    vector<int> t(m);
    vector<int> p(m);

    int tm=0;
    int pm=0;

    string ans="Yes";


    for (int i=0;i<m;i++)
        cin>>t[i]>>p[i];

    for (int i=0;i<m;i++){

        if (t[i]-tm>=abs(pm-p[i])){
            tm=t[i];
            pm=p[i];
        }
        else{
            ans="No";
            break;
        }


    }
    cout<<ans<<endl;
    
}