#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }


void visit(const vector<vector<int> > &g, int v,
		vector<int> &scccolor, int &colors,
		vector<int> &S, vector<char> &inS,
		vector<int> &low, vector<int> &num, int& time) {
	low[v] = num[v] = ++time;
	S.push_back(v); inS[v] = true;
	each(e, g[v]) {
		int w = *e;
		if (num[w] == 0) {
			visit(g, w, scccolor, colors, S, inS, low, num, time);
			low[v] = min(low[v], low[w]);
		} else if (inS[w])
			low[v] = min(low[v], num[w]);
	}
	if (low[v] == num[v]) {
		while (1) {
			int w = S.back(); S.pop_back(); inS[w] = false;
			scccolor[w] = colors;
			if (v == w) break;
		}
		colors ++;
	}
}
int stronglyConnectedComponents(const vector<vector<int> >& g,
		vector<int>& scccolor) {
	const int n = g.size();
	vector<int> num(n), low(n);
	vector<int> S;
	vector<char> inS(n);
	scccolor.resize(n);
	int time = 0, colors = 0;
	rep(u, n) if (num[u] == 0)
		visit(g, u, scccolor, colors, S, inS, low, num, time);
	return colors;
}

bool two_satisfiability(const vector<vi> &g) {
	int n = g.size() / 2;
	vi scccolor;
	stronglyConnectedComponents(g, scccolor);
	rep(i, n) if(scccolor[i] == scccolor[n+i]) return false;
	return true;
}

inline bool commonPoint1D(int a, int b, int c, int d) {
	return c <= b && a <= d;
}

int main() {
	int N, M;
	while(cin >> N >> M) {
		vi L(N), R(N);
		rep(i, N)
			scanf("%d%d", &L[i], &R[i]);
		vector<vi> g(N * 2);
		rep(i, N) rep(j, i) {
			int a = L[i], b = R[i], c = L[j], d = R[j];
			rep(x, 2) {
				rep(y, 2) {
					if(commonPoint1D(a, b, c, d)) {
						g[x * N + i].push_back((1-y) * N + j);
						g[y * N + j].push_back((1-x) * N + i);
					}

					a = M - 1 - a, b = M - 1 - b, swap(a, b);
				}
				c = M - 1 - c, d = M - 1 - d, swap(c, d);
			}
		}
		bool ans = two_satisfiability(g);
		puts(ans ? "YES" : "NO");
	}
	return 0;
}