#include<bits/stdc++.h>
using namespace std;
struct jm{
	int ks;
	int js;
}a[110];
int n;
bool cmp(jm x,jm y){
return  x.js<y.js;
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>a[i].ks>>a[i].js;
	}
    sort(a+1,a+1+n,cmp);
    int c=1;
    int end=a[1].js;
    for(int i=2;i<=n;i++){
    	if(a[i].ks>=end){
    		c++;
    		end=a[i].js;
    	}
    }
    cout<<c;

	return 0;
}

/**************************************************************
	Problem: 1372
	User: chenlingxuan
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2076 kb
****************************************************************/