#include <bits/stdc++.h>
#include <bits/stdc++.h>
#include <bits/stdc++.h>
using namespace std;
// #include <atcoder/modint>
// using namespace atcoder;
// using mint = modint998244353;
using ll = long long;
#define fix(x) fixed << setprecision(x)
#define rep(i, n) for(int i = 0; i < n; ++i)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,h;
    cin >> n >> h;
    vector<int> imos(h+1,0);
    while(n--){
        int a,b;
        cin >> a >> b;
        ++imos[a];
        --imos[b+1];
    }
    int ans = 0;
    rep(i,h){
        chmax(ans, imos[i]);
        imos[i+1] += imos[i];
    }
    cout << ans << '\n';
    return 0;
}