#include <bits/stdc++.h>
#define EPS 1e-9
#define INF 1070000000LL
#define MOD 1000000007LL
#define fir first
#define foreach(it,X) for(auto it=(X).begin();it!=(X).end();it++)
#define numa(x,a) for(auto x: a)
#define ite iterator
#define mp make_pair
#define rep(i,n) rep2(i,0,n)
#define rep2(i,m,n) for(int i=m;i<(n);i++)
#define pb push_back
#define pf push_front
#define sec second
#define sz(x) ((int)(x).size())
#define ALL( c ) (c).begin(), (c).end()
#define gcd(a,b) __gcd(a,b)
#define mem(x,n) memset(x,n,sizeof(x))
#define endl "\n"
using namespace std;
template <int POS, class TUPLE> void deploy(std::ostream &os, const TUPLE &tuple){}
template <int POS, class TUPLE, class H, class ...Ts> void deploy(std::ostream &os, const TUPLE &t){ os << (POS == 0 ? "" : ", ") << get<POS>(t); deploy<POS + 1, TUPLE, Ts...>(os, t); }
template <class T,class U> std::ostream& operator<<(std::ostream &os, std::pair<T,U> &p){ os << "(" << p.first <<", " << p.second <<")";return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::vector<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }
template <class T> std::ostream& operator<<(std::ostream &os, std::set<T> &v){ int remain = v.size(); os << "{"; for(auto e: v) os << e << (--remain == 0 ? "}" : ", "); return os; }
template <class T, class K> std::ostream& operator<<(std::ostream &os, std::map<T, K> &mp){ int remain = mp.size(); os << "{"; for(auto e: mp) os << "(" << e.first << " -> " << e.second << ")" << (--remain == 0 ? "}" : ", "); return os; }
#define DEBUG1(var0) { std::cerr << (#var0) << "=" << (var0) << endl; }
#define DEBUG2(var0, var1) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG1(var1); }
#define DEBUG3(var0, var1, var2) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG2(var1,var2); }
#define DEBUG4(var0, var1, var2, var3) { std::cerr << (#var0) << "=" << (var0) << ", ";DEBUG3(var1,var2,var3); }
using ll = long long;
pair <int,int> nums[2010];
bool OK[2010][2];
int N, M;
pair <int,int> rev(pair <int,int> x){
  return mp(M - x.sec, M - x.fir);
}
bool cross(pair <int,int> x, pair <int,int> y){
  if (x > y) {
    swap(x,y);
  }
  return y.fir - x.sec <= 0;
}
bool assign(pair <int,int> s, int x){//[i,j]
  rep2(i,x+1,N){
    OK[i][0] &= !cross(s, nums[i]);
    OK[i][1] &= !cross(s, rev(nums[i]));
  }
  return true;
}

bool test(pair <int,int> s, int x){//[i,j]
  rep2(i,x+1,N){
    if (OK[i][0] && !cross(s,nums[i])) {
      continue;
    }
    if (OK[i][1] && !cross(s, rev(nums[i]))) {
      continue;
    }
    return false;
  }
  return true;
}


bool update(int x){
  if (OK[x][0]) {
    if (test(nums[x], x)) {
      assign(nums[x], x);
      return true;
    }
  }
  if (OK[x][1]) {
    if (test(rev(nums[x]), x)) {
      assign(rev(nums[x]), x);
      return true;
    }
  }
  return false;
}
int main()
{
  cin.tie(0);
  ios_base::sync_with_stdio(0);
  rep(i,2010){
    rep(j,2){
      OK[i][j] = true;
    }
  }

  cin >> N >> M;
  M--;
  rep(i,N){
    cin >> nums[i].fir >> nums[i].sec;
  }
  rep(i,N){
    auto b = update(i);
    if (!b) {
      cout << "NO\n";
      return 0;
    }
  }
  cout << "YES\n";
  return 0;
}