#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 using namespace std;

 struct node

 {

     int x;

     int y;

 }a[];

 int comp(const node & a , const  node & b)

 {

     return a.y<b.y;

 }

 int main()

 {

     int n;

     scanf("%d",&n);

     for(int i=;i<=n;i++)

     {

         scanf("%d%d",&a[i].x,&a[i].y);

         if(a[i].x>a[i].y)

         swap(a[i].x,a[i].y);

     }

     sort(a+,a+n+,comp);

     int last=-;

     int ans=;

     for(int i=;i<=n;i++)

     {

         if(a[i].x>=last)

         {

             ans++;

             last=a[i].y;

         }

     }

     printf("%d",ans);

     return ;

 }