#ifdef LOCAL111
	#define _GLIBCXX_DEBUG
#else
	#define NDEBUG
#endif
#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
const int INF = 1e9;
using namespace std;
template<typename T, typename U> ostream& operator<< (ostream& os, const pair<T,U>& p) { cout << '(' << p.first << ' ' << p.second << ')'; return os; }

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#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(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
	template<typename T> void dpite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
#else
	#define DEBUG(x) true
	template<typename T> void dpite(T a, T b){ return; }
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}



typedef long long cost_t;

class Edge {
public:
	int to = -1, from = -1, rev = -1;
	cost_t cost = -1;
	
	Edge(){
	}

	Edge(int x,cost_t y){
		to = x;
		cost = y;
	}

	Edge(int x, int y, cost_t z){
		from = x;
		to = y;
		cost = z;
	}

	Edge(int x, int y, int r, cost_t z){
		from = x;
		to = y;
		cost = z;
		rev = r;
	}

	bool operator< (const Edge& x) const {
		if(cost != x.cost) return cost < x.cost;
		return to < x.to;
	}

	bool operator> (const Edge& x) const {
		if(cost != x.cost) return cost > x.cost;
		return to > x.to;
	}
};

class Graph {
private:
	typedef vector<Edge> Edges;
	//const long long int INF = (long long)1e18;
	vector<Edges> v; 
	int n;
public:
	Graph(int x){
		n = x;
		v = vector<Edges>(x);
	}

	Graph(){}

	Edges& operator[](int x){
		return v[x];
	}

	const Edges& operator[](int x) const {
		return v[x];
	}

	int size() const {
		return n;
	}

	void add_edge(int from, Edge e){
		v[from].push_back(e);
	}

	void add_edge(int from, int to, cost_t cost = -1, int rev = -1){
		add_edge(from,Edge(from,to,rev,cost));
	}

	void add_uedge(int from, int to, cost_t cost = -1){
		add_edge(from,to,cost);
		add_edge(to,from,cost);
	}
};

void vizGraph(const Graph &g, bool with_dir = false, bool with_cap = false){
	ofstream ofs("./out.dot");
	if(with_dir) ofs << "graph graph_name {" << endl;
	else ofs << "digraph graph_name {" << endl;
	
	for(int i = 0; i < (int)g.size(); ++i) {
		ofs << "    " << i << '[' << endl;
		ofs << "    " << "];" << endl << endl;
	}

	for(int i = 0; i < (int)g.size(); ++i){
		if (!g[i].size())
			continue;
		for(const auto &e : g[i]){
			if(with_dir){
				if(e.to > i) ofs << "    " << i << " -- " << e.to ; 
			}else ofs << "    " << i << " -> " << e.to ; 
			if (with_cap) {
				ofs << " [ label = " << (e.cost  == INF ? "inf" : to_string(e.cost)) << "];"; 
			}
			if(!with_dir or e.to > i)ofs << endl;
		}
	}
	ofs << "}" << endl;
	ofs.close();
	system("dot -T png out.dot > sample.png");	
}


//未検証
vector<int> toposort(const Graph &g)
{
	int n = g.size();
	vector<int> res;
	res.reserve(n);
	vector<bool> used(n,false);
	function<void(int)> rec = [&](int p){
		if(used[p]) return;
		used[p] = true;
		for(auto&& e : g[p]) {
			rec(e.to);
		}
		res.push_back(p);
	};
	for(int i = 0; i < n; ++i) {
		if(!used[i]) rec(i);
	}
	return res;
}
//library

tuple<vector<int>,int> SCC(const Graph &g)
{
	int n = g.size();
	vector<bool> used(n,false);
	vector<int> cmp(g.size());
	Graph rg(n);
	for(int i = 0; i < n; ++i) {
		for(auto&& e : g[i]) {
			rg.add_edge(e.to,i,e.cost);
		}
	}
	vector<int> vs;
	vs.reserve(g.size());
	
	function<void(int)> dfs = [&](int v){
		used[v] = true;
		for(auto&& e : g[v]) {
			if(!used[e.to]) dfs(e.to);
		}
		vs.push_back(v);
	};

	function<void(int,int)> rdfs = [&](int v, int k){
		used[v] = true;
		cmp[v] = k;
		for(auto&& e : rg[v]) {
			if(!used[e.to]) rdfs(e.to,k); 
		}
	};

	for(int v = 0; v < n; ++v) {
		if(!used[v]) dfs(v);
	}
	fill(used.begin(), used.end(), false);
	int k = 0;
	for(int i = n-1; i >= 0; --i) {
		if(!used[vs[i]]) rdfs(vs[i], k++);
	}
	return make_tuple(cmp,k);
}

Graph getSCCGraph(const Graph &g, vector<int> cmp, int k){
	Graph res(k);
	for(int p = 0; p < (int)g.size(); ++p) {
		for(auto&& e : g[p]) {
			res.add_edge(cmp[p],cmp[e.to],e.cost,e.rev);
		}
	}
	return res;
}

//liblary

//Graph, toposort, scc に依存
class TwoSATsolver{
private:
	Graph g;
	int center;

public:
	TwoSATsolver(int n){
		center = n;
		g = Graph(2*n+1);
	}

	int f(int x){
		return center+x;
	}

	void add_clause(int x, int y){
		g.add_edge(f(-y),f(x));
		g.add_edge(f(-x),f(y));
	}

	//充足不可能なら空のvectorを返す
	vector<bool> solve(){
		// vizGraph(g);
		vector<int> cmp;
		int k;
		tie(cmp,k) = SCC(g);
		Graph retg = getSCCGraph(g,cmp,k);

		for(int i = 1; i <= center; ++i) {
			if(cmp[f(i)] == cmp[f(-i)]){
				return vector<bool>();
			}
		}

		vector<bool> res(center+1);
		vector<int> topo = toposort(retg);
		dpite(ALL(topo));
		vector<int> rtopo(k);
		for(int i = 0; i < k; ++i) {
			rtopo[topo[i]] = i;
		}
		for(int i = 1; i <= center; ++i) {
			int cmpi = cmp[f(i)];
			int cmpni = cmp[f(-i)];
			assert(rtopo[cmpi] != rtopo[cmpni]);
			if(rtopo[cmpi] > rtopo[cmpni]){
				res[i] = false;
			}else{
				res[i] = true;
			}
		}
		return res;
	}
};

typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<int,int> P;

void ios_init(){
	//cout.setf(ios::fixed);
	//cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}

int main()
{
	ios_init();
	int n,m;
	while(cin >> n >> m) {
		vector<P> lr(n);
		REP(i,n) cin >> lr[i].F >> lr[i].S;
		
		auto rev = [&](P p) -> P{
			return {m-1-p.S,m-1-p.F};
		};
		auto intersect = [&](P x, P y) -> bool{
			return (x.F <= y.F and y.F <= x.S) or
					(x.F <= y.S and y.S <= x.S);
		};
		TwoSATsolver s(n);
		REP(i,n) REP(j,i){
			P r1 = lr[i];
			P r2 = lr[j];
			if(intersect(r1,r2)){
				DEBUG(1);
				s.add_clause(-(i+1),-(j+1));
			}
			if(intersect(r1,rev(r2))){
				DEBUG(2);
				s.add_clause(-(i+1),(j+1));
			}
			if(intersect(rev(r1),r2)){
				DEBUG(3);
				s.add_clause((i+1),-(j+1));
			}
			if(intersect(rev(r1),rev(r2))){
				DEBUG(4);
				s.add_clause((i+1),(j+1));
			}
		}
		auto ret = s.solve();
		dpite(ALL(ret));
		if(ret.size() == 0){
			cout << "NO" << endl;
		}else{
			cout << "YES" << endl;
		}
	}
	return 0;
}