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

#define RREP(i,s,e) for (i = s; i >= e; i--)
#define rrep(i,n) RREP(i,n,0)
#define REP(i,s,e) for (i = s; i < e; i++)
#define rep(i,n) REP(i,0,n)
#define INF 100000000

typedef long long ll;

int main() {
    int i, n, m;
    int a[4001] {};
    bool ans;
    cin >> n >> m;
    rep (i,n) {
        int l, r;
        cin >> l >> r;
        a[l]++; a[r+1]--;
    }
    rep (i,m) a[i+1] += a[i];
    ans = true;
    rep (i,m) {
        if (a[i] > 2 || a[i] == 2 && a[m-i-1] != 0)
            ans = false;
    }
    if (ans)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}