#include<bits/stdc++.h>
using namespace std;

const int N=1e5+10,INF=0x3f3f3f3f;
int n;
struct Range{
    int l,r;

    bool operator <(const Range &W)const{
        return r<W.r;
    }
}range[N];

int main(){
    cin>>n;
    for(int i=0;i<n;i++){
        int a,b;
        cin>>a>>b;
        range[i]={a,b};
    }

    sort(range,range+n);

    int res=0,ed=-INF;
    for(int i=0;i<n;i++){
        if(range[i].l>ed){
            res++;
            ed=range[i].r;
        }
    }
    cout<<res<<endl;
}