#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using mint = atcoder::static_modint<998244353>;
// // using mint = atcoder::static_modint<1000000007>;
using ld = long double;
using ll = long long;
#define mp(a,b) make_pair(a,b)
#define rep(i,s,n) for(int i=s; i<(int)n; i++)
const vector<int> dx{1,0,-1,0},dy{0,1,0,-1};

int main(){
    int n,h;cin >> n >> h;
    vector<int> table(h+10);
    rep(i,0,n){
        int a,b;cin >> a >> b;
        table[a]++;
        table[b+1]--;
    }

    rep(i,1,h+10)table[i]+=table[i-1];
    cout << *max_element(table.begin(),table.end());
}