#include <iostream>
#include <algorithm>
using namespace std;

class range {private: struct I{int x;int operator*(){return x;}bool operator!=(I& lhs){return x<lhs.x;}void operator++(){++x;}};I i,n;
public:range(int n):i({0}),n({n}){}range(int i,int n):i({i}),n({n}){}I& begin(){return i;}I& end(){return n;}};

int n, m, N;
vector<vector<int>> G1, G2;
vector<bool> visited;
vector<int> cmp, stk;

void nya(int v) {
  visited[v] = true;
  for(int vv : G1[v]) {
    if(visited[vv]) { continue; }
    nya(vv);
  }
  stk.push_back(v);
}

void nyaa(int v, int cnt) {
  visited[v] = true;
  for(int vv : G2[v]) {
    if(visited[vv]) { continue; }
    nyaa(vv, cnt);
  }
  cmp[v] = cnt;
}

int scc() {
  visited.assign(N, false);
  cmp.assign(N, 0);
  stk.clear();
  for(int v : range(N)) {
    if(visited[v]) { continue; }
    nya(v);
  }
  visited.assign(N, false);
  int cnt = 0;
  while(!stk.empty()) {
    int v = stk.back(); stk.pop_back();
    if(visited[v]) { continue; }
    nyaa(v, cnt++);
  }
  return cnt;
}

void add_edge(int v0, int v1) {
  G1[v0].push_back(v1);
  G2[v1].push_back(v0);
}

void add_edges(int i, int j) {
  add_edge(i, j);
  int x = i>=n ? i-n : i+n,
      y = j>=n ? j-n : j+n;
  add_edge(y, x);
}

int rev(int x) { return m-x-1; }

int main(void) {
  scanf("%d%d", &n, &m);
  vector<int> l(n), r(n);
  for(int i : range(n)) {
    scanf("%d%d", &l[i], &r[i]);
  }
  N = 2 * n;
  G1.assign(N, vector<int>());
  G2.assign(N, vector<int>());
  for(int i : range(n)) {
    int li0 = l[i], li1 = rev(r[i]),
        ri0 = r[i], ri1 = rev(l[i]);
    for(int j : range(i+1, n)) {
      int lj0 = l[j], lj1 = rev(r[j]),
          rj0 = r[j], rj1 = rev(l[j]);
      if(li0 <= rj0 && lj0 <= ri0) { add_edges(i,   n+j); }
      if(li1 <= rj0 && lj0 <= ri1) { add_edges(n+i, n+j); }
      if(li0 <= rj1 && lj1 <= ri0) { add_edges(i,   j  ); }
      if(li1 <= rj1 && lj1 <= ri1) { add_edges(n+i, j  ); }
    }
  }
  scc();
  for(int i : range(n)) {
    if(cmp[i] == cmp[n+i]) {
      puts("NO");
      return 0;
    }
  }
  puts("YES");
  return 0;
}