#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, h;
  cin >> n >> h;
  vector<int> sum(h + 1);
  rep(_, n) {
    int a, b;
    cin >> a >> b;
    sum[a]++, sum[b + 1]--;
  }
  rep(i, h) sum[i + 1] += sum[i];
  int ans = 0;
  rep(i, h + 1) ans = max(ans, sum[i]);
  cout << ans << '\n';
  return 0;
}