#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

void solve() {
  ll n, h;
  cin >> n >> h;
  vector<vector<ll>> bs(h + 10);
  rep(i, n) {
    ll a, b;
    cin >> a >> b;
    bs[a].push_back(b);
  }
  ll ans = 0;
  priority_queue<ll> que;
  rep(i, h + 5) {
    while (!que.empty()) {
      ll b = que.top();
      if (-b < i) {
        que.pop();
      } else {
        break;
      }
    }
    for (const auto b : bs[i]) {
      que.push(-b);
    }
    ans = max<ll>(ans, que.size());
  }
  cout << ans << '\n';
}

int main() {
  std::cin.tie(nullptr);
  std::ios_base::sync_with_stdio(false);
  int T = 1;
  for (int t = 0; t < T; t++) {
    solve();
  }
  return 0;
}