#include <bits/stdc++.h>

using namespace std;

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
#define fi first
#define se second

template<typename A, typename B> inline bool chmax(A &a, B b) { if (a<b) { a=b; return 1; } return 0; }
template<typename A, typename B> inline bool chmin(A &a, B b) { if (a>b) { a=b; return 1; } return 0; }

typedef unsigned long long ull;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, pii> P;

const ll INF = 1ll<<29;
const ll MOD = 1000000007;
const double EPS  = 1e-10;

int n, m;
int l[2000], r[2000], rl[2000], rr[2000];
int cnt[4001];
bool done[2000];

int main() {
	cin >> n >> m;
	REP(i, n) {
		scanf("%d %d", l + i, r + i);
		cnt[l[i]]++;
		cnt[r[i] + 1]--;
		
		rl[i] = m - r[i] - 1;
		rr[i] = m - l[i] - 1;
		
		cnt[rl[i]]++;
		cnt[rr[i] + 1]--;
	}
	
	FOR(i, 1, m) cnt[i] += cnt[i - 1];
	
	while (true) {
		bool cont = false;
		
		REP(i, n) if (!done[i]) {
			bool ok = false;
			
			bool ng = false;
			FOR(j, l[i], r[i] + 1) if (cnt[j] > 2) ng = true;
			if (!ng) ok = true;
			
			ng = false;
			FOR(j, rl[i], rr[i] + 1) if (cnt[j] > 2) ng = true;
			if (!ng) ok = true;
			
			if (ok) {
				done[i] = true;
				FOR(j, l[i], r[i] + 1) cnt[j]--;
				FOR(j, rl[i], rr[i] + 1) cnt[j]--;
				cont = true;
			}
		}
		
		if (!cont) break;
	}
	
	bool ans = true;
	REP(i, m) if (cnt[i]) ans = false;
	
	puts(ans ? "YES" : "NO");
	
	return 0;
}