#include<iostream>
#include<algorithm>
using namespace std;
int dp[200005],n;
struct node{
	int S,N;
}a[200005];
bool cmp(node x,node y){
	return x.N<y.N;
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i].S>>a[i].N;
	}
	sort(a+1,a+n+1,cmp);
	int num=1;
	dp[num]=a[1].S;
	for(int i=1;i<=n;i++){
		int x=lower_bound(dp+1,dp+num+1,a[i].S)-dp;
		dp[x]=a[i].S;
		if(x>num) num++;
	}
	cout<<num;
	return 0;
}