#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

bool sw=true;
struct Info{
    int id,x1,x2;
    friend bool operator<(Info& a,Info& b){
        if(sw)
            return (a.x1==b.x1)?(a.x2<b.x2):(a.x1<b.x1);
        else
            return (a.x2==b.x2)?(a.x1<b.x1):(a.x2<b.x2);
    }
};

int main(){
    int i;
    int n,m;
    cin>>n>>m;
    vector<Info> v;
    for(i=0;i<n;i++){
        Info io1,io2;
        io1.id=io2.id=i;
        int x1,x2;
        cin>>x1>>x2;
        io1.x1=x1;io1.x2=x2;
        io2.x1=m-x1-1;io2.x2=m-x2-1;
        if(io2.x1>io2.x2)swap(io2.x1,io2.x2);
        v.push_back(io1);
        v.push_back(io2);
    }
    sort(v.begin(),v.end());
    bool t[2000]={0};
    int bef=-1;
    for(i=0;i<(int)v.size();i++){
        if(!t[v[i].id]&&v[i].x1>bef){
            bef=v[i].x2;
            t[v[i].id]=true;
        }
    }
    for(i=0;i<n;i++){
        if(!t[i])
            break;
    }
    if(i==n){
        cout<<"YES"<<endl;
        return 0;
    }
    sw=false;
    sort(v.begin(),v.end());
    for(i=0;i<n;i++)t[i]=false;
    bef=m;
    for(i=v.size()-1;i>=0;i--){
        if(!t[v[i].id]&&v[i].x2<bef){
            bef=v[i].x1;
            t[v[i].id]=true;
        }
    }
    for(i=0;i<n;i++){
        if(!t[i])
            break;
    }
    if(i==n){
        cout<<"YES"<<endl;
    }
    else
        cout<<"NO"<<endl;
    return 0;
}