#include <bits/stdc++.h> using namespace std; #define REP(i,n) for(ll i=0;i<(ll)n;i++) #define dump(x) cerr << #x << " = " << (x) << endl; #define spa << " " << #define fi first #define se second #define ALL(a) (a).begin(),(a).end() #define ALLR(a) (a).rbegin(),(a).rend() using ld = long double; using ll = long long; using ull = unsigned long long; using pii = pair<int, int>; using pll = pair<long, long>; using pdd = pair<ld, ld>; template<typename T> struct V : vector<T> { using vector<T>::vector; }; V() -> V<ll>; V(size_t) -> V<ll>; template<typename T> V(size_t, T) -> V<T>; template<typename T> vector<T> make_vec(size_t n, T a) { return vector<T>(n, a); } template<typename... Ts> auto make_vec(size_t n, Ts... ts) { return vector<decltype(make_vec(ts...))>(n, make_vec(ts...)); } template<class S, class T> ostream& operator << (ostream& os, const pair<S, T> v){os << "(" << v.first << ", " << v.second << ")"; return os;} template<typename T> ostream& operator<<(ostream &os, const vector<T> &v) { for (auto &e : v) os << e << ' '; return os; } template<class T> ostream& operator<<(ostream& os, const vector<vector<T>> &v){ for(auto &e : v){os << e << "\n";} return os;} struct fast_ios { fast_ios(){ cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; } template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; } void fail() { cout << -1 << '\n'; exit(0); } inline int popcount(const int x) { return __builtin_popcount(x); } inline int popcount(const ll x) { return __builtin_popcountll(x); } template<typename T> void debug(vector<vector<T>>&v,ll h,ll w){for(ll i=0;i<h;i++) {cerr<<v[i][0];for(ll j=1;j<w;j++)cerr spa v[i][j];cerr<<endl;}}; template<typename T> void debug(vector<T>&v,ll n){if(n!=0)cerr<<v[0]; for(ll i=1;i<n;i++)cerr spa v[i]; cerr<<endl;}; const ll INF = (1ll<<62); // const ld EPS = 1e-10; // const ld PI = acos(-1.0); const ll mod = (int)1e9 + 7; //const ll mod = 998244353; int main(){ ll N, M; cin >> N >> M; V<ll> T(M), P(M); REP(i, M) cin >> T[i] >> P[i]; ll pos = 0; ll now = 0; REP(i, M){ if(T[i]-now>=abs(P[i]-pos)){ now = T[i]; pos = P[i]; }else{ cout << "No" << endl; return 0; } } cout << "Yes" << endl; return 0; }