#include<bits/stdc++.h>
using namespace std;
struct jm{
	int ks;
	int js;
}a[250];
bool cmp(jm s,jm y){
return s.js<y.js;
}
int n;
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,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: wangyousi
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2080 kb
****************************************************************/