#include<bits/stdc++.h> 
using namespace std;
using ll=long long;

void solve(){
	ll N,H;cin>>N>>H;
	vector<pair<ll,ll>> P;
	for(int i=0;i<N;i++){
		ll A,B;
		cin>>A>>B;
		P.push_back({A,-1});
		P.push_back({B,1});
	}
	sort(P.begin(),P.end());
	ll bn=0,an=0;
	for(auto [p,k]:P){
		bn+=k;
		an=min(an,bn);
	}
	cout<<-an<<endl;

}

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

	int T=1;
	// cin>>T;
	while(T--)solve();
}