#include"bits/stdc++.h"
using namespace std;
#define REP(k,m,n) for(int (k)=(m);(k)<(n);(k)++)
#define rep(i,n) REP((i),0,(n))
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using tp3 = tuple<int, int, int>;
using Mat = vector<vector<ll>>;
constexpr int INF = 1 << 28;
constexpr ll INFL = 1ll << 60;
constexpr int dh[4] = { 0,1,0,-1 };
constexpr int dw[4] = { -1,0,1,0 };
bool isin(const int H, const int W, const int h, const int w) {
    return 0 <= h && h < H && 0 <= w && w < W;
}
// ============ template finished ============

int main()
{
    ll N, M;
    cin >> N >> M;
    vector<pll> tp(M);
    rep(i, M)cin >> tp[i].first >> tp[i].second;
    tp.insert(tp.begin(), make_pair(0ll, 0ll));

    bool safe = true;
    rep(i, M) {
        ll diffT = abs(tp[i].first - tp[i + 1].first);
        ll diffP = abs(tp[i].second - tp[i + 1].second);
        safe &= (diffT >= diffP);
    }
    cout << (safe ? "Yes" : "No") << endl;
    return 0;
}