#include <iostream>
#include <cmath>
#include <stack>
#include <iomanip>
#include <limits>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <deque>
#include <atcoder/all>
#include <unordered_set>
using namespace atcoder;
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define Yes cout << "Yes" << endl
#define No cout << "No" << endl
#define vl vector<long long>
#define vvl vector<vector<long long>>
#define vvvl vector<vector<vector<long long>>>
#define vc vector<char>
#define vvc vector<vector<char>>
#define vb vector<bool>
#define vvb vector<vector<bool>>
#define nall(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define yu_qgrid(x, y) ((x) * (x) + (y) * (y)) // ユークリッド距離 (sqrtはしない)
#define mannhattan(x1, x2, y1, y2) abs(x1 - x2) + abs(y1 - y2)
#define PI 3.14159265359
using ll = long long;
using mint = modint1000000007;
// using mint = modint998244353;
using P = pair<ll, ll>;

vl di = {1, 0, -1, 0}; // 下、左、上、右
vl dj = {0, -1, 0, 1};


bool out_grid(ll i, ll j, ll h, ll w) { return !(0 <= i && i < h && 0 <= j && j < w); }

ll INF = 1e18;
int main(){
    ll n,h;
    cin >> n >> h;
    
    vl s(h+1);
    rep(i,n){
        ll a,b;
        cin >> a >> b;
        s[a]++;s[b+1]--;
    }

    for(int i = 0;i < h;i++){
        s[i+1] += s[i];
    }
    ll ans = 0;
    for(int i = 0;i < h+1;i++){
        chmax(ans,s[i]);
    }
    cout << ans << endl;
    return 0;
}