#include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <queue>

#include <map>
#include <set>
#include <string>
#include <algorithm>
#include <functional>
#include <iterator>

using namespace std;

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define INF (1<<30)
#define ALEN(ARR) (sizeof(ARR) / sizeof((ARR)[0]))
#define MP make_pair
#define mp make_pair
#define pb push_back
#define PB push_back

#if DEBUG
#define _DEBUG(x) cout<<#x<<": "<<x<<endl
#define _DDEBUG(x,y) cout<<#x<<": "<<x<<", "<<#y<<": "<<y<<endl
#else
#define _DEBUG(x) ;
#define _DDEBUG(x,y) ;
#endif

#define ll long long
#define ull unsigned long long
#define MOD 1000000007

/** FOR VECTOR DEBUG */
template <typename T>
ostream& operator<< (ostream& out, const vector<T>& v) {
    if ( !v.empty() ) {
        out << '[';
        copy (v.begin(), v.end(), ostream_iterator<T>(out, ", "));
        out << "\b\b]";
    }
    return out;
}


/* template end */
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout.precision(16);

    int n, m;
    cin >> n >> m;

    int c = 0, ct = 0;
    bool b = true;
    for(int i = 0; i < m; i++) {
        int t, p;
        cin >> t >> p;
        int d = t - ct;
        int max_ = c + d, min_ = c - d;
        bool f = p >= c ? p <= max_ : min_ <= p;
        if(f) {
            c = p, ct = t;
        } else {
            b = false;
            break;
        }
    }

#if DEBUG
    cout << "** RESULT **" << endl; // debug
#endif
    cout << (b ? "Yes" : "No") << endl;

    return 0;
}