#include <cstdio>
#include <cstring>
#include <cmath>
#include <climits>
#include <iostream>
#include <iomanip>
#include <list>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <set>
#include <string>
#include <utility>
#include <algorithm>
#include <numeric>
#include <functional>

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define ALL(a) (a).begin(),(a).end()

using namespace std;
typedef long long ll;

int N, M, L, R, center;
int dp[4010];

int main(int argc, char *argv[])
{
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> N >> M;
  REP(i,N) {
    cin >> L >> R;
    RFOR(j,L,R+1) dp[j]++;
    int l2 = M-1-R;
    int r2 = M-1-L;
    RFOR(j,l2,r2+1) dp[j]++;
  }

  REP(i,M) {
    if (dp[i] > 2) {
      cout << "NO" << endl;
      return 0;
    }
  }
  cout << "YES" << endl;
      

  return 0;
}