#include <bits/stdc++.h>
using namespace std;
      ifstream in("int.in");
      ofstream out("int.out");
    struct st
    {
        int x,y;
    }a[50005];
bool cmp( const st &a, const st &b ) { return ( a.y<b.y );}
int main()
{
    int n; in>>n;
    for( int i=1; i<=n; i++ )
    {
        in>>a[i].x>>a[i].y;
    }
    sort(a+1,a+n+1,cmp);
    int k=0;
    int verific = -(1<<30);

    for ( int i=1; i<=n; i++ )
    {
        if(verific  <= a[i].x ) { k++; verific =a[i].y; }
    }
    out<<k;
    return 0;
}