#include<cstdio>

 #include<cstring>

 #include<algorithm>

 #include<cmath>

 using namespace std;

 int i,j,n,ans = ,beg;

 struct node

 {

     int sta;

     int mo;

 }a[];

 int cmp(node a,node b)

 {

     return a.mo < b.mo;

 }

 int main()

 {

     scanf("%d",&n);

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

     {

         scanf("%d %d",&a[i].sta,&a[i].mo);

     }

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

     ans = ;

     beg = a[].mo;

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

     {

         if(a[i].sta >= beg)

         {

             ans++;

             beg = a[i].mo;

         }

     }

     printf("%d",ans);

     return ;

 }