#include <bits/stdc++.h>

using namespace std;

#define FOR(i,s,e) for(int (i)=(s);(i)<(int)(e);(i)++)
#define REP(i,e) FOR(i,0,e)

#define all(o) (o).begin(), (o).end()
#define psb(x) push_back(x)

typedef long long ll;

typedef struct edge_def {
  int from;
  int to;
  int cost;

  edge_def(int _from, int _to, int _cost) {
    from = _from;
    to   = _to;
    cost = _cost;
  };
} edge;

struct SCC {
  int nv; //頂点数
  vector<vector<edge>> edges_forward;
  vector<vector<edge>> edges_backward;
  vector<int> usd;       //確定したかチェック用
  vector<int> vs;        //帰りがけ順の並び
  vector<int> cmp;       //強連結成分のトポロジカル順序

  SCC(int nv) {
    this->nv = nv;
    edges_forward.resize(nv);
    edges_backward.resize(nv);
    usd.resize(nv);
    cmp.resize(nv);
  }

  inline void set_edge(int from, int to, int weight) {
    edges_forward[from].psb(edge(from,to,weight));
    edges_backward[to].psb(edge(to,from,weight));
  }

  void decompose_dfs_forward(int v) {
    usd[v] = 1;
    REP(i,(int)edges_forward[v].size())
      if (!usd[edges_forward[v][i].to]) decompose_dfs_forward(edges_forward[v][i].to);
    vs.psb(v);
  }

  void decompose_dfs_backward(int v, int k) {
    usd[v] = 1;
    cmp[v] = k;
    REP(i,(int)edges_backward[v].size()) 
      if (!usd[edges_backward[v][i].to]) decompose_dfs_backward(edges_backward[v][i].to, k);
  }

  int decompose() {
    fill(all(usd), 0);
    vs.clear();
    REP(v,nv) if (!usd[v]) decompose_dfs_forward(v);

    fill(all(usd), 0);
    int k = 0;
    REP(i,(int)vs.size()) 
      if (!usd[vs[vs.size()-1-i]]) 
        decompose_dfs_backward(vs[vs.size()-1-i], k++);

    return k; //decomp scc後のnodeの数
  }
};

const int N = 2000;
const int M = 4000;
int n, m;
int l[N], r[N];

int main() {
  scanf("%d%d ", &n, &m);
  REP(i,n) scanf("%d%d ", l+i, r+i); 

  SCC scc(n*2);
  REP(i,n) REP(j,i) {
    int a = l[i], b = r[i], c = l[j], d = r[j];
    REP(k,4) {
      if (k==2) {a = m - 1 - a; b = m - 1 - b; swap(a,b);}
      if (k>0)  {c = m - 1 - c; d = m - 1 - d; swap(c,d);}
      int x = k/2, y = k&1;  
      if (max(a,c) <= min(b,d)) {
        scc.set_edge((1-x)*n+i,y*n+j,0);
        scc.set_edge((1-y)*n+j,x*n+i,0);
      }
    }
  }

  scc.decompose();
  int res = 1;
  REP(i,n) if (scc.cmp[i]==scc.cmp[n+i]) {
    res = 0;
    break; 
  }
  printf("%s\n", res ? "YES" : "NO");

  return 0;
}