#include <bits/stdc++.h>
using namespace std;

typedef long long   signed int LL;
typedef long long unsigned int LU;

#define incID(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define incII(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define decID(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define decII(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define  inc(i, n) incID(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define  dec(i, n) decID(i, 0, n)
#define dec1(i, n) decII(i, 1, n)

#define inII(v, l, r) ((l) <= (v) && (v) <= (r))
#define inID(v, l, r) ((l) <= (v) && (v) <  (r))

#define PB push_back
#define EB emplace_back
#define MP make_pair
#define FI first
#define SE second
#define UB upper_bound
#define LB lower_bound
#define PQ priority_queue

#define  ALL(v)  v.begin(),  v.end()
#define RALL(v) v.rbegin(), v.rend()
#define  FOR(it, v) for(auto it =  v.begin(); it !=  v.end(); ++it)
#define RFOR(it, v) for(auto it = v.rbegin(); it != v.rend(); ++it)

template<typename T> bool   setmin(T & a, T b) { if(b <  a) { a = b; return true; } else { return false; } }
template<typename T> bool   setmax(T & a, T b) { if(b >  a) { a = b; return true; } else { return false; } }
template<typename T> bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } }
template<typename T> bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

int n, m, b[2000];
vector<int> l, r;

bool solve() {
	inc(i, l.size()) {
		if(m / 2 <= r[i]) {
			r[i] = m - 1 - r[i];
			l[i] = m - 1 - l[i];
			swap(l[i], r[i]);
		}
		if(m / 2 <= r[i]) {
			l.PB(m - 1 - r[i]);
			r.PB((m - 2) / 2);
			r[i] = (m - 1) / 2;
		}
	}
	inc(i, l.size()) {
		incII(j, l[i], r[i]) { b[j]++; }
	}
	if(m % 2 == 1) { b[m / 2] *= 2; }
	
	int ma = 0;
	inc(i, (m + 1) / 2) { setmax(ma, b[i]); }
	
	return (ma <= 2);
}

int main() {
	cin >> n >> m;
	inc(i, n) {
		int ll, rr;
		cin >> ll >> rr;
		l.PB(ll);
		r.PB(rr);
	}
	
	cout << (solve() ? "YES" : "NO") << endl;
	
	return 0;
}