#include <bits/stdc++.h>
using namespace std;

using ll = long long;

int main()
{
    int N, H;
    cin >> N >> H;
    
    vector<pair<int, bool>> v;
    for (int i = 0; i < N; i++)
    {
        int a, b;
        cin >> a >> b;
        b++;
        v.emplace_back(a, false);
        v.emplace_back(b, true);
    }

    sort(v.begin(), v.end());

    int p = 0;
    int current = 0;
    int ans = 0;
    while (p < v.size())
    {
        pair<int, bool> f = v[p++];
        if (f.second) current--;
        else current++;
        while (p < v.size() && v[p].first == f.first)
        {
            if (v[p].second) current--;
            else current++;
            p++;
        }

        ans = max(ans, current);
    }

    cout << ans << endl;
}