#include<iostream>
using namespace std;
//Strongly Connected Components
#include<vector>
struct SCC{
	int n;
	vector<int>comp,order;
	vector<bool>used;
	vector<vector<int> >G,RG;
	SCC(int _n=0):n(_n),comp(_n,-1),used(_n,false),G(_n),RG(_n){}
	void add_edge(int from,int to)
	{
		G[from].push_back(to);
		RG[to].push_back(from);
	}
	void copy(const vector<vector<int> >&H)
	{
		for(int i=0;i<H.size();i++)
		{
			for(int j=0;j<H[i].size();j++)
			{
				G[i].push_back(H[i][j]);
				RG[H[i][j]].push_back(i);
			}
		}
	}
	int operator[](int u)const{return comp[u];}
	void dfs(int u)
	{
		used[u]=true;
		for(int i=0;i<G[u].size();i++)if(!used[G[u][i]])dfs(G[u][i]);
		order.push_back(u);
	}
	void rdfs(int u,int cnt)
	{
		comp[u]=cnt;
		for(int i=0;i<RG[u].size();i++)if(comp[RG[u][i]]==-1)rdfs(RG[u][i],cnt);
	}
	int build()
	{
		for(int i=0;i<n;i++)if(!used[i])dfs(i);
		int cnt=0;
		for(int i=n-1;i>=0;i--)if(comp[order[i]]==-1)rdfs(order[i],cnt++);
		return cnt;
	}
	int build(vector<vector<int> >&H)
	{
		int ret=build();
		H.assign(ret,vector<int>());
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<G[i].size();j++)
			{
				if(comp[i]!=comp[G[i][j]])
					H[comp[i]].push_back(comp[G[i][j]]);
			}
		}
		return ret;
	}
};
int N,M;
int L[2000],R[2000];
main()
{
	cin>>N>>M;
	for(int i=0;i<N;i++)cin>>L[i]>>R[i];
	SCC P(2*N);
	for(int i=0;i<2*N;i++)for(int j=0;j<2*N;j++)
	{
		int l1=L[i/2],r1=R[i/2],l2=L[j/2],r2=R[j/2];
		if(i%2==1)
		{
			int t=l1;
			l1=M-1-r1;
			r1=M-1-t;
		}
		if(j%2==1)
		{
			int t=l2;
			l2=M-1-r2;
			r2=M-1-t;
		}
		if(!(i==j||r1<l2||r2<l1))
		{
			P.add_edge(i,j^1);
			P.add_edge(j,i^1);
		}
	}
	P.build();
	for(int i=0;i<N;i++)
	{
		if(P[i*2]==P[i*2+1])
		{
			cout<<"NO"<<endl;
			return 0;
		}
	}
	cout<<"YES"<<endl;
}