#include<iostream>

#include<cstring>

#include<cstdio>

#include<algorithm>

#define MAXN 2000005

using namespace std;

struct cc{

    int bg,ed;

}nod[MAXN];

bool cmp(cc a,cc b){

    if(a.ed==b.ed) return a.bg<b.bg;

    else return a.ed<b.ed;

}

int N,p=1,lst_time,ans;

int main(){

//    freopen("01.in","r",stdin);

    scanf("%d",&N);

    for(int i=1;i<=N;i++){scanf("%d%d",&nod[i].bg,&nod[i].ed);}

    sort(nod+1,nod+N+1,cmp);

    for(int i=0;i<=1000005&&p<=N;i++){

        while( p<=N && ( nod[p].ed<i || lst_time>nod[p].bg ) ) ++p;

//        cout<<nod[p].bg<<" "<<nod[p].ed<<endl;

        if(nod[p].ed==i&&p<=N&&lst_time<=nod[p].bg){

            lst_time=i;

            ++ans;

            ++p;

        }

    }

    cout<<ans<<endl;

    return 0;

}