#include<deque>
#include<queue>
#include<vector>
#include<algorithm>
#include<iostream>
#include<set>
#include<cmath>
#include<tuple>
#include<string>
#include<chrono>
#include<functional>
#include<iterator>
#include<random>
#include<unordered_set>
#include<array>
#include<map>
#include<iomanip>
#include<assert.h>
using namespace std;
typedef long long int llint;
typedef long double lldo;
#define mp make_pair
#define mt make_tuple
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define fir first
#define sec second
#define res resize
#define ins insert
#define era erase
//cout<<setprecision(20)
//cin.tie(0);
//ios::sync_with_stdio(false);
const llint mod=1000000007;
const llint big=4.19e18+1;
const long double pai=3.141592653589793238462643383279502884197;
const long double eps=1e-15;
template <class T,class U>void mineq(T& a,U b){if(a>b){a=b;}}
template <class T,class U>void maxeq(T& a,U b){if(a<b){a=b;}}
llint gcd(llint a,llint b){if(a%b==0){return b;}else return gcd(b,a%b);}
llint lcm(llint a,llint b){return a/gcd(a,b)*b;}
template<class T> void SO(T& ve){sort(ve.begin(),ve.end());}
template<class T> void REV(T& ve){reverse(ve.begin(),ve.end());}
int LBI(vector<int>&ar,llint in){return lower_bound(ar.begin(),ar.end(),in)-ar.begin();}
int UBI(vector<int>&ar,llint in){return upper_bound(ar.begin(),ar.end(),in)-ar.begin();}
int main(void){
	set<int>x;
	set<int>nai;
	int i,n;cin>>n;
	for(i=1;i<=100000+100;i++){nai.ins(i);}
	while(n--){
		llint a,b;cin>>a>>b;
		auto itr=x.lower_bound(b);
		if(itr!=x.end()){
			nai.ins(*itr);
			x.era(itr);
		}
		int in=*nai.lower_bound(a);
		nai.era(in);
		x.ins(in);
		
	}
	cout<<x.size()<<endl;
	return 0;
}