#include <iostream>
#include <vector>
#include <algorithm>
#include <map>
#include <queue>
#include <cstdio>
#include <ctime>
#include <assert.h>
#include <chrono>
#include <random>
#include <numeric>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
using namespace std;
typedef long long int ll;
typedef unsigned long long ull;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll myRand(ll B) {
    return (ull)rng() % B;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,m; cin >> n >> m;
    bool ok=true;
    int now=0;
    ll cur=0;
    vector<ll> t(m),p(m);
    for(int i=0;i<m;i++){
        cin >> t[i] >> p[i];
        if(t[i]-cur<abs(p[i]-now)){
            ok=0;
        }
        cur=t[i];
        now=p[i];
    }
    if(ok)printf("Yes\n");
    else printf("No\n");

}