#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int INF = 1e9;
const ll LINF = 1e18;
template<class S,class T> ostream& operator << (ostream& out,const pair<S,T>& o){ out << "(" << o.first << "," << o.second << ")"; return out; }
template<class T> ostream& operator << (ostream& out,const vector<T> V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; }
template<class T> ostream& operator << (ostream& out,const vector<vector<T> > Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; }
template<class S,class T> ostream& operator << (ostream& out,const map<S,T> mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; }

/*
 <url:https://yukicoder.me/problems/no/274>
 問題文============================================================
 =================================================================
 解説=============================================================
 ================================================================
 */

struct BIT {
    int N;
    vector<ll> bit1;
    vector<ll> bit2;
    BIT(ll N):N(N) {
        /* BITは[1..N]で扱う */
        bit1.resize(N + 1, 0);
        bit2.resize(N + 1, 0);
    }
    
    void add1(int x, ll val){
        while (x <= N) {
            bit1[x] += val;
            x += x & -x;
        }
    }
    void add2(int x, ll val){
        while (x <= N) {
            bit2[x] += val;
            x += x & -x;
        }
    }
    
    // [l,r]
    void RangeAdd(int l,int r,ll val){
        // Update BIT1
        add1(l,val);
        add1(r+1,-val);
        
        // Update BIT2
        add2(l,val*(l-1));
        add2(r+1,-val*r);
    }
    
    ll sum1(int x){
        ll ret = 0;
        while (x) {
            ret += bit1[x];
            x &= (x - 1);
        }
        return (ret);
    }
    
    ll sum2(int x){
        ll ret = 0;
        while (x) {
            ret += bit2[x];
            x &= (x - 1);
        }
        return (ret);
    }
    
    ll sum(int x){
        return sum1(x)*x - sum2(x);
    }
    // [l,r]
    ll RangeSum(int l,int r){
        return sum(r) - sum(l-1);
    }
};
string solve(){
    int N,M; cin >> N >> M;
    BIT bit(M+1);
    for(int i = 0; i < N;i++){
        int L,R; cin >> L >> R;
        L++; R++;
        int L2 = M+1-R,R2 = M+1-L;
        int LL,LR,RL,RR;
        if(L <= L2){
            LL = L; LR = R;
            RL = L2; RR = R2;
        }else{
            LL = L2; LR = R2;
            RL = L; RR = R;
        }
        if(bit.RangeSum(LL, LR)==0){
            bit.RangeAdd(LL,LR,1);
        }else{
            if(bit.RangeSum(RL,RR)==0){
                bit.RangeAdd(RL,RR,1);
            }else{
                return "NO";
            }
        }
    }
    return "YES";
}
int main(void) {
    cin.tie(0); ios_base::sync_with_stdio(false);
    cout << solve() << endl;
    return 0;
}