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

int main() {
    int n, m; cin >> n >> m;
    vector<int> l(n), r(n);
    auto reverse = [&](int &l, int &r) {
        l = m - 1 - l, r = m - 1 - r;
        swap(l, r);
    };
    for (int i = 0; i < n; i++) {
        cin >> l[i] >> r[i];
        if (m - 1 - r[i] < l[i]) reverse(l[i], r[i]);
    }
    vector<int> used(n);
    for (int i = 0, left = 0; i < n; i++) {
        int num = -1;
        for (int j = 0; j < n; j++) if (!used[j]) {
            if (l[j] < left) reverse(l[j], r[j]);
            if (l[j] < left) return cout << "NO" << endl, 0;
            if (num == -1 || l[j] < l[num]) num = j;
        }
        left = r[num] + 1, used[num] = true;
    }
    cout << "YES" << endl;
    return 0;
}