#include<bits/stdc++.h>
using namespace std;
int n,ans=1;
struct Node{
	int x,y;
}a[100];
bool cmp(Node c,Node d){
   return c.y<d.y;
}
int main(){
    cin>>n;
    for(int i=1;i<=n;i++){
    		cin>>a[i].x>>a[i].y;	
    }
    sort(a+1,a+n+1,cmp);
    int y=a[1].y;
    for(int i=2;i<=n;i++){
    	int z=a[i].x;
    	if(z>=y){
    	ans++;
		y=a[i].y;	
    	}
    }
    cout<<ans;
	return 0;
}

/**************************************************************
	Problem: 1372
	User: chenjingqi
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2076 kb
****************************************************************/