#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001

int main(){
	
	int n;
	cin>>n;
	
	vector<int> a(n),b(n);
	vector<int> t;
	rep(i,n){
		cin>>a[i]>>b[i];
		t.push_back(a[i]);
		t.push_back(b[i]);
	}
	sort(t.begin(),t.end());
	t.erase(unique(t.begin(),t.end()),t.end());
	vector<vector<int>> E(t.size());
	rep(i,n){
		a[i]=lower_bound(t.begin(),t.end(),a[i])-t.begin();
		b[i]=lower_bound(t.begin(),t.end(),b[i])-t.begin();
		E[b[i]].push_back(a[i]);
	}
	
	multiset<int> S;
	rep(i,t.size()){
		rep(j,E[i].size()){
			auto it = S.upper_bound(E[i][j]);
			if(it==S.begin()){
				S.insert(i);
			}
			else{
				it--;
				S.erase(it);
				S.insert(i);
			}
		}
	}
	cout<<S.size()-1<<endl;
	return 0;
}