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

typedef pair<int, int> PII;

const int N=1e5+5;
vector<PII> INV;
int n;

int main(){
    cin>>n;
    for(int i=0; i<n; ++i){
        int start, end;
        cin>>start>>end;
        INV.push_back({start, end});
    }

    // sort intervals
    sort(INV.begin(), INV.end(), [&](PII p1, PII p2){
        if(p1.first == p2.first)
            return p1.second<p2.second;
        return p1.first<p2.first;
    });

    // merge intervals
    int cnt=1;
    PII curINV = *INV.begin();
    for(auto it = next(INV.begin()); it!=INV.end(); ++it){
        if(it->first<=curINV.second) curINV.second = max(curINV.second, it->second);
        else{
            curINV=*it;
            cnt++;
        }
    }
    cout<<cnt<<endl;

    return 0;
}