#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
	int n, m; cin >> n >> m;
	vector<int>blocks(m+1);

	for (int i = 0; i < n; i++) {
		int l, r; cin >> l >> r;
		if (l > m - 1 - l || r < m - 1 - r) {
			blocks[l]++;
			blocks[r + 1]--;
			blocks[m - 1 - r]++;
			blocks[m - l]--;
		}
		else {
			l = min(l, m - 1 - r);
			r = max(r, m - 1 - l);
			blocks[l]++;
			blocks[r + 1]--;
		}
	}
	for (int i = 0; i < m; i++) {
		if (blocks[i] > 2) {
			cout << "NO" << endl;
			return 0;
		}
		blocks[i+1] += blocks[i];
	}
	cout << "YES" << endl;
    return 0;
}