#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<ctime>
#include<queue>
#include<set>
#include<map>
#include<stack>
#include<bitset>
using namespace std;
typedef long long LL;
const int N=1e6;
int gi() {
	int w=0;bool q=1;char c=getchar();
	while ((c<'0'||c>'9') && c!='-') c=getchar();
	if (c=='-') q=0,c=getchar();
	while (c>='0'&&c <= '9') w=w*10+c-'0',c=getchar();
	return q? w:-w;
}
int mx[N],sum[N],m;
vector<int>v[N];
#define lc (i<<1)
#define rc (lc|1)
inline void modify(int i,int l,int r,int k,int t) {
	if (l==r) mx[i]+=t,sum[i]+=t;
	else {
		int mid=(l+r)>>1;
		k<=mid?modify(lc,l,mid,k,t):modify(rc,mid+1,r,k,t);
		sum[i]=max(sum[lc]+sum[rc],-1<<28);
		mx[i]=max(mx[rc],mx[lc]+sum[rc]);
	}
}
inline void build(int i,int l,int r) {
	if (l==r) sum[i]=mx[i]=l<m?-1:0;
	else {
		int mid=(l+r)>>1;
		build(lc,l,mid);
		build(rc,mid+1,r);
		sum[i]=max(sum[lc]+sum[rc],-1<<28);
		mx[i]=max(mx[rc],mx[lc]+sum[rc]);
	}
}
int main()
{
	int n=gi(),i,k,ans=max(0,n-(m=gi()));
	while (n--) k=gi(),v[k].push_back(gi());
	build(1,1,++m);
	for (i=0;i<m;modify(1,1,m,++i,-1<<28)) {
		for (int t:v[i])
			modify(1,1,m,t,1);
		ans=max(ans,mx[1]-i);
	}
	printf("%d\n",ans);
	return 0;
}
