#include <fstream>
#include <algorithm>

using namespace std;

ifstream fin ("reactivi.in");
ofstream fout ("reactivi.out");

struct islife
{
    int x,y;

}v[8010];

 bool cmp (islife a,islife b)
    {
        if (a.x==b.x) return a.y<b.y;
        return a.x<b.x;
    }

int n,i,fr,a,b,aux;

int main()
{
    fin >> n;
    for (i=1;i<=n;i++)
    {
        fin>> v[i].x>>v[i].y;
    }
        sort (v+1,v+n+1,cmp);

        a=v[1].x;
        b=v[1].y;
        for (i=2;i<=n;i++)
        {
            if ( v[i].x <= b && v[i].x>=a)
            {
                a=v[i-1].y;
                b=v[i].x;
                if (a>b)
                {
                    aux=b;
                    b=a;
                    a=aux;
                }
            }
            else
            {
                fr++;
            }
        }
    fout << fr+1;



    return 0;
}