#include <bits/stdc++.h>
using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;

int main() {
    int n, m;
    cin >> n >> m;
    vvi adj(n * 2);
    using ii = pair<int, int>;
    vector<ii> lr;
    for (int i = 0; i < n; i++) {
        int l, r;
        cin >> l >> r;
        lr.push_back(ii(l, r));
        adj[i].push_back(i + n);
        adj[i + n].push_back(i);
    }

    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            ii a = lr[i], b = lr[j];
            if (a > b) swap(a, b);
            if (b.first <= a.second) {
                adj[i].push_back(j);
                adj[j].push_back(i);
                adj[i + n].push_back(j + n);
                adj[j + n].push_back(i + n);
            }
            b = ii(m - 1 - b.second, m - 1 - b.first);
            if (a > b) swap(a, b);
            if (b.first <= a.second) {
                adj[i + n].push_back(j);
                adj[j].push_back(i + n);
                adj[i].push_back(j + n);
                adj[j + n].push_back(i);
            }
        }
    }

    int ok = 1;
    vi color(2 * n, -1);
    unordered_set<int> unvisited;
    for (int i = 0; i < 2 * n; i++) {
        unvisited.insert(i);
    }
    function<void(int, int)> dfs = [&](int v, int c) {
        if (color[v] == -1) {
            unvisited.erase(v);
            color[v] = c;
            for (int s: adj[v]) {
                dfs(s, !c);
            }
        } else {
            if (color[v] != c) {
                ok = 0;
            }
        }
    };
    while (unvisited.size()) {
        int t = *unvisited.begin();
        dfs(t, 0);
    }
    cout << (ok ? "YES" : "NO") << endl;
}