#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, e) for (int i = (int)(s); i < (int)(e); ++i)
#define all(a) (a).begin(),(a).end()

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    
    int N, H;
    cin >> N >> H;
    vector<int> sum(H, 0);
    rep(i, 0, N) {
        int A, B;
        cin >> A >> B;
        ++sum[A];
        if (B != H - 1) --sum[B + 1];
    }
    rep(i, 1, H) sum[i] += sum[i - 1];
    
    int ans = 0;
    rep(i, 0, H) ans = max(ans, sum[i]);
    cout << ans << '\n';
}