#include <bits/stdc++.h>
#define ALL(x) (x).begin(), (x).end()
#define LB(v, x) (int)(lower_bound(ALL(v), x) - v.begin())
#define UQ(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define IO ios::sync_with_stdio(false), cin.tie(nullptr);
#define chmax(a, b) (a) = (a) < (b) ? (b) : (a)
#define chmin(a, b) (a) = (a) < (b) ? (a) : (b)
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

int main() {
    int N, H;
    cin >> N >> H;

    vector<int> io(H + 2);
    for (int i = 0; i < N; i++) {
        int a, b;
        cin >> a >> b;
        b++;
        io[a]++, io[b]--;
    }

    int ans = 0;
    for (int i = 0; i < H; i++) {
        chmax(ans, io[i]);
        io[i + 1] += io[i];
    }

    cout << ans << endl;
}