//yukicoder contest 458 D
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    ll N, H;
    cin >> N >> H;
    vector<ll> A(N), B(N);
    for(ll i = 0; i < N; i ++) cin >> A[i] >> B[i];

    ll a = 0, ans = 0;
    vector<ll> table(H + 1);
    for(ll i = 0; i < N; i ++) table[A[i]] ++, table[B[i] + 1] --;
    for(ll i = 0; i < H + 1; i ++) a += table[i], ans = max(ans, a);

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