#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint998244353;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vmi = vector<mint>;
using vvmi = vector<vmi>;
using vvvmi = vector<vvmi>;
#define all(a) (a).begin(), (a).end()
#define rep2(i, m, n) for (int i = (m); i < (n); ++i)
#define rep(i, n) rep2(i, 0, n)
#define drep2(i, m, n) for (int i = (m)-1; i >= (n); --i)
#define drep(i, n) drep2(i, n, 0)

int main(){
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int n, h; cin >> n >> h;
    vector<pair<int, int>> vp(n);
    rep(i, n){
        int a, b; cin >> a >> b;
        vp[i] = {a, b};
    }
    sort(all(vp));
    priority_queue<int, vector<int>, greater<int>> pq;
    int itr = 0;
    int ans = 0;
    rep(i, h){
        while(itr < n && vp[itr].first <= i){
            pq.push(vp[itr].second);
            itr++;
        }ans = max(ans, (int)pq.size());
        while(!pq.empty() && pq.top() <= i){
            pq.pop();
        }

    }
    cout << ans << endl;
    return 0;
}