#include<bits/stdc++.h>
using namespace std;
int n,maxx=INT_MIN,ct,i;
struct nod
{
    int x,y;
}v[50001];
bool cmp(nod i,nod j)
{
    return i.x<j.x;
}
ifstream f("int.in");
ofstream g("int.out");
int main()
{
    f>>n;
    for(i=1; i<=n; ++i)
        f>>v[i].y>>v[i].x;
    sort(v+1,v+n+1,cmp);
    for(i=1; i<=n; ++i)
        if(v[i].y>=maxx)
        {
            maxx=v[i].x;
            ct++;
        }
    g<<ct;
    return 0;
}