#include<bits/stdc++.h>
using namespace std;
struct hlq{
    int x,y;
}a[1000];
bool cmp(hlq c,hlq d){
    return c.y<d.y;
}
int main(){
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>a[i].x>>a[i].y;
    } 
    sort(a+1,a+1+n,cmp);
    int ans=1,e=a[1].y;
    for(int i=2;i<=n;i++){
        if(a[i].x>=e){
            ans++;
            e=a[i].y;
        }
    }
    cout<<ans;  
    return 0;
}
/**************************************************************
	Problem: 1372
	User: wangsenlin
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2084 kb
****************************************************************/