#include <bits/stdc++.h>
using namespace std;

using pii = pair<int,int>;
using ll = long long;
#define rep(i, j) for(int i=0; i < (int)(j); i++)
#define repeat(i, j, k) for(int i = (j); i < (int)(k); i++)
#define all(v) v.begin(),v.end()
#define debug(x) cerr << #x << " : " << x << endl

template<class T> bool set_min(T &a, const T &b) { return a > b  ? a = b, true : false; }
template<class T> bool set_max(T &a, const T &b) { return a < b  ? a = b, true : false; }
// vector
template<class T> istream& operator >> (istream &is , vector<T> &v) { for(T &a : v) is >> a; return is; }
template<class T> ostream& operator << (ostream &os , const vector<T> &v) { for(const T &t : v) os << "\t" << t; return os << endl; }
// pair
template<class T, class U> ostream& operator << (ostream &os , const pair<T, U> &v) { return os << "<" << v.first << ", " << v.second << ">"; }

const int INF = 1 << 30;
const ll INFL = 1LL << 60;


class Solver {
  public:
    bool solve() {
        int N, M; cin >> N >> M;
        vector<int> L(N), R(N);
        rep(i, N) cin >> L[i] >> R[i];
        vector<int> used(M);

        rep(i, N) {
            bool ok = true;
            repeat(j, L[i], R[i] + 1) ok &= not used[j];
            if(not ok) {
                swap(L[i], R[i]);
                L[i] = M - 1 - L[i];
                R[i] = M - 1 - R[i];
                ok = true;
                repeat(j, L[i], R[i] + 1) ok &= not used[j];
            }
            if(not ok) {
                cout << "NO" << endl;
                return 0;                
            }
            repeat(j, L[i], R[i] + 1) used[j] = true;            
        }
        cout << "YES" << endl;        
        return 0;
    }
};

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    Solver s;
    s.solve();
    return 0;
}