#include<iostream>
#include<vector>
#include<functional>
using namespace std;

template<typename T>
class DualSegmentTree
{
private:
	int n;
	vector<T> node;
	std::function<T(T,T)> op;
	T e;
public:
	DualSegmentTree(vector<T> vec,function<T(T,T)> op,T e)
	{
		n = 1;
		while(n < (int)vec.size()) n <<= 1;
		this->op = op;
		this->e = e;
		node.resize(n*2,e);
		for(int i = 0; i < (int)vec.size(); ++i)
		{
			node[i+n] = vec[i];
		}
	}

	void update(int l,int r,T x)
	{
		l += n;
		r += n;
		while(l < r)
		{
			if(l & 1)
			{
				node[l] = op(node[l],x);
				++l;
			} 
			if(r & 1)
			{
				--r;
				node[r] = op(node[r],x);
			}
			l >>= 1, r >>= 1;
			
		}
	}

	T GetNode(int i)
	{
		i += n;
		T x = e;
		while(i != 0)
		{
			x = op(x,node[i]);
			i >>= 1;
		}
		return x;
	}

};

int op(int a,int b)
{
	return a + b;
}
int main()
{
	int N,H;
	cin >> N >> H;
	vector<int> v(H+20,0);
	DualSegmentTree<int> segtree(v,op,0);
	for(int i=0;i<N;++i)
	{
		int a,b;
		cin >> a >> b;
		--a;
		segtree.update(a,b,1);
	}

	int ans = 0;
	for(int i=0;i<H;++i)
	{
		ans = max(ans,segtree.GetNode(i));
	}
	cout << ans << endl;
}