#include<bits/stdc++.h>
using namespace std;
struct jm{
	int ks;
	int js;
}a[110];
int n;
bool cmp(jm x,jm y){
//    if(x.js<y.js){
//    	return true;	
//    }
//    else return false;
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: hulaoshi
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2076 kb
****************************************************************/