#include <bits/stdc++.h>

using namespace std;

#define INF 100000000
#define YJ 1145141919
#define INF_INT_MAX 2147483647
#define INF_LL_MAX 9223372036854775807
#define EPS 1e-10
#define Pi acos(-1)
#define LL long long
#define ULL unsigned long long
#define LD long double

using namespace std;

//変数は1-index
class SAT_2{
public:
  SAT_2(int aN)
  {
    init(aN);
  }

  //変数の数
  void init(int aN)
  {
    N = aN;
    VecSize = 2 * N + 1;
    Edge.resize(VecSize);
    rEdge.resize(VecSize);
    used.resize(VecSize);
    vs.clear();
    cmp.resize(VecSize);
  }

  //節を登録
  void reg(int l, int r)
  {
    int tmpL = l, tmpR = r;
    tmpL *= -1;
    tmpL += N, tmpR += N;
    Edge[tmpL].push_back(tmpR);
    rEdge[tmpR].push_back(tmpL);

    tmpL = r, tmpR = l;
    tmpL *= -1;
    tmpL += N, tmpR += N;
    Edge[tmpL].push_back(tmpR);
    rEdge[tmpR].push_back(tmpL);
  }

  void dfs(int v)
  {
    used[v] = true;
    for (int i = 0; i < Edge[v].size(); i++) {
      if(!used[Edge[v][i]]){
        dfs(Edge[v][i]);
      }
    }
    vs.push_back(v);
  }

  void rdfs(int v, int k){
    used[v] = true;
    cmp[v] = k;
    for (int i = 0; i < rEdge[v].size(); i++) {
      if(!used[rEdge[v][i]]){
        rdfs(rEdge[v][i], k);
      }
    }
  }

  int scc()
  {
    for (int i = 0; i < used.size(); i++) {
      used[i] = false;
    }
    vs.clear();
    for (int i = 0; i < VecSize; i++) {
      if(!used[i]) dfs(i);
    }

    for (int i = 0; i < used.size(); i++) {
      used[i] = false;
    }

    int k = 0;
    for (int i = vs.size()-1; 0 <= i; i--) {
      if(!used[vs[i]]){
        rdfs(vs[i], k++);
      }
    }

    return k;
  }

  bool checkSatisfy()
  {
    scc();
    for(int i = 0; i < N; i++){
      if(cmp[i] == cmp[i+N+1]){
        return false;
      }
    }

    return true;
  }

private:
  vector<vector<int>> Edge;
  vector<vector<int>> rEdge;
  vector<bool> used;
  vector<int> vs; //帰りがけ順の並び
  vector<int> cmp; //属する連結成分のトポロジカル順序

  int N;
  int VecSize;
};

#define MAX_N 2005
#define MAX_M 4005

int N, M;
int L[MAX_N], R[MAX_N];

//衝突しているか
bool checkCollision(int l1, int r1, int l2, int r2)
{
  if(r1 < l1){
    swap(l1, r1);
  }

  if(r2 < l2){
    swap(l2, r2);
  }

  if(l1 <= l2 && l2 <= r1){
    return true;
  }

  if(l1 <= r2 && r2 <= r1){
    return true;
  }

  return false;
}

int main()
{

  cin >> N >> M;
  for (int i = 1; i <= N; i++) {
    cin >> L[i] >> R[i];
  }

  SAT_2 sat(N);

  for (int i = 1; i <= N; i++) {
    for (int j = i+1; j <= N; j++) {
      if(i == j){
        continue;
      }
      if(checkCollision(L[i], R[i], L[j], R[j])){
        sat.reg(i, j);
      }
      if(checkCollision(L[i], R[i], M - 1 - L[j], M - 1 - R[j])){
        sat.reg(i, -j);
      }
      if(checkCollision(M - 1 - L[i], M - 1 - R[i], L[j], R[j])){
        sat.reg(-i, j);
      }
      if(checkCollision(M - 1 - L[i], M - 1 - R[i], M - 1 - L[j], M - 1 - R[j])){
        sat.reg(-i, -j);
      }
    }
  }

  if(sat.checkSatisfy()){
    cout << "YES" << endl;
  }
  else{
    cout << "NO" << endl;
  }

  return 0;
}