#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;
int main(void){
    // Here your code !
    int N, M;
    cin >> N >> M;
    vector< vector<int> > ls(M);
    vector<int> counts(M);
    
    for(int i=0;i<N;i++){
        int l, r;
        cin >> l >> r;
        if(M-1-r<l){
            int l2,r2;
            l2 = M-1-r;
            r2 = M-1-l;
            l=l2;
            r=r2;
        }
        //cout << "l=" << l << ", r=" << r << endl;
        ls[l].push_back(r);
    }
    for(int l=0;l<M;l++){
        vector<int> rs = ls[l];
        sort(rs.begin(), rs.end());
        reverse(rs.begin(), rs.end());
        if(rs.size()==0){
            continue;
        }
        if(rs.size()>2){
            cout << "NO" << endl;
            exit(0);
        }
        if(counts[l]==1){
            {
                int r = rs[0];
                //cout << "rs[1]: l=" << l << ", r=" << r << endl;
                
                int l2 = M-1-r;
                int r2 = M-1-l;
                //cout << "rs[1]: l2=" << l2 << ", r2=" << r2 << endl;
                for(int i=l2;i<=r2;i++){
                    counts[i]++;
                }
            }
        }else{
            {
                int r = rs[0];
                //cout << "rs[0]: l=" << l << ", r=" << r << endl;
                for(int i=l;i<=r;i++){
                    counts[i]++;
                }
            }
            if(rs.size()==2){
                int r = rs[1];
                //cout << "rs[1]: l=" << l << ", r=" << r << endl;
                
                int l2 = M-1-r;
                int r2 = M-1-l;
                //cout << "rs[1]: l2=" << l2 << ", r2=" << r2 << endl;
                for(int i=l2;i<=r2;i++){
                    counts[i]++;
                }
            }
        }
    }
    bool flag = true;
    for(int i=0;i<M;i++){
        if(counts[i]>=2){
            flag = false;
        }
        //cout << "counts[" << i << "]=" << counts[i] << endl;
    }
    if(flag){
        cout << "YES" << endl;
    }else{
        cout << "NO" << endl;
    }
    return 0;
}