#include <bits/stdc++.h>
//#include <atcoder/modint>

using namespace std;
//using namespace atcoder;
using ll = long long;
//using mint = modint998244353;

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    int N, H, a, b, mx=0;
    cin >> N >> H;
    vector<int> c(H+1);
    for (int i=0; i<N; i++){
        cin >> a >> b;
        c[a]++;
        c[b+1]--;
    }
    mx = c[0];
    for (int i=1; i<=H; i++){
        c[i] += c[i-1];
        mx = max(mx, c[i]);
    }
    cout << mx << endl;

    return 0;
}