#include <cstdio>
#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <cstring>
#include <sstream>
#include <algorithm>
#include <functional>
#include <queue>
#include <stack>
#include <cmath>
#include <iomanip>
#include <list>
#include <tuple>
#include <bitset>
#include <ciso646>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;

inline bool cheak(ll x, ll y, ll xMax, ll yMax){ return x >= 0 && y >= 0 && xMax > x && yMax > y; }
inline ll toInt(string s) { ll v; istringstream sin(s); sin >> v; return v; }
template<class T> inline string toString(T x) { ostringstream sout; sout << x; return sout.str(); }
template<class T> inline T sqr(T x) { return x*x; }

#define For(i,a,b)	for(ll (i) = (a);i < (b);(i)++)
#define rep(i,n)	For(i,0,n)
#define rFor(i,a,b)	for(ll (i) = (a-1);i >= (b);(i)--)
#define rrep(i,n)	rFor(i,n,0)
#define clr(a)		memset((a), 0 ,sizeof(a))
#define mclr(a)		memset((a), -1 ,sizeof(a))
#define all(a)		(a).begin(),(a).end()
#define sz(a)		(sizeof(a))

const int dx[8] = { 1, 0, -1, 0, 1, 1, -1, -1 }, dy[8] = { 0, -1, 0, 1, -1, 1, -1, 1 };
const ll mod = 1e9 + 7;
const ll INF = 1e9 + 2;

int n, m;

bool base[5000];

void reverse_LR(int &L,int &R){
	int r =  m - L - 1;
	int l = (m - R - 1);
	L = l, R = r;
}
bool ok(int L,int R){
	for (int j = L; j <= R; j++){
		if (base[j])return false;
	}
	return true;
}

int main(){
	cin >> n >> m;

	rep(i, n){
		int L, R;
		cin >> L >> R;
		if (ok(L, R) == false){
			reverse_LR(L, R);
			if (ok(L, R) == false){
				cout << "NO" << endl;
				return 0;
			}
		}
		for (int j = L; j <= R; j++){
			base[j] = true;
		}
	}
	cout << "YES" << endl;
	
	return 0;
}