#include <bits/stdc++.h>
using namespace std;
// #include<atcoder/all>
// using mint = atcoder::modint998244353;
using ld = long double;
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define chmax(a,b) a=max(a,b)
#define chmin(a,b) a=min(a,b)

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int N,H;
    cin>>N>>H;
    vector<int> A(H+1,0);
    rep(i,N){
        int a,b;
        cin>>a>>b;
        A[a]++;
        A[b+1]--;
    }
    rep(i,H) A[i+1]+=A[i];
    int ans=0;
    rep(i,H+1) chmax(ans, A[i]);
    cout<<ans<<"\n";
}