#include<sstream>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
using namespace std;
#define INF (1<<29)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define uniq(v) v.erase(unique(all(v)),v.end())
#define indexOf(v,x) (find(all(v),x)-v.begin())



int n,m;
pair<int,int> b[2000];


bool cmp(pair<int,int> a,pair<int,int> b){
	int x=min(a.first,m-1-a.second);
	int y=min(b.first,m-1-b.second);
	return x<y;
}

int main(){	
	cin>>n>>m;
	rep(i,n)cin>>b[i].first>>b[i].second;
	sort(b,b+n,cmp);
	bool used[2000]={};
	bool filled[4000]={};
	rep(i,n){
		bool ok=true;
		if(b[i].first < m-1-b[i].second){
			for(int j=b[i].first;j<=b[i].second;j++){
				if(filled[j])ok=false;
			}
			if(ok){
				for(int j=b[i].first;j<=b[i].second;j++){
					filled[j]=true;
				}
				used[i]=true;
			}
		}else{
			for(int j=m-1-b[i].second;j<=m-1-b[i].first;j++){
				if(filled[j])ok=false;
			}
			if(ok){
				for(int j=m-1-b[i].second;j<=m-1-b[i].first;j++){
					filled[j]=true;
				}
				used[i]=true;
			}
		}
	}
	rep(i,n){
		if(used[i])continue;
		bool ok=true;
		if(b[i].first < m-1-b[i].second){
			for(int j=m-1-b[i].second;j<=m-1-b[i].first;j++){
				if(filled[j])ok=false;
			}
			if(ok){
				for(int j=m-1-b[i].second;j<=m-1-b[i].first;j++){
					filled[j]=true;
				}
				used[i]=true;
			}
		}else{
			for(int j=b[i].first;j<=b[i].second;j++){
				if(filled[j])ok=false;
			}
			if(ok){
				for(int j=b[i].first;j<=b[i].second;j++){
					filled[j]=true;
				}
				used[i]=true;
			}
		}
	}
	cout<<(count(used,used+n,true)==n?"YES":"NO")<<endl;
	return 0;
}