#include<bits/stdc++.h>
using namespace std;
struct cpt{
    int b;
    int e;
    int l=e-b;
};
bool cmp(const cpt&x,const cpt&y){
    if(x.b!=y.b){return x.b<y.b;}
    else{ return x.l<y.l;}
      
}
cpt c[1000005];
int main(){
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>c[i].b>>c[i].e;
    }
    sort(c,c+n,cmp);
    int cnt=1;
    int begin=c[0].b,end=c[0].e;
    for(int i=1;i<n;i++){
        if(end<=c[i].b){cnt++;end=c[i].e;}
    }
    cout<<cnt;
}