#include <iostream>

#include <vector>

#include <algorithm>

using namespace std;

bool cmp(pair<int, int> a, pair<int, int> b){

return a.first < b.first;

}

int main(void){

ios::sync_with_stdio(false);

cin.tie(0);

int N;

cin>>N;

pair<int, int> arr[101];

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

int from,to;

cin>>from>>to;

arr[i] = make_pair(from,to);

}

sort(arr, arr+N, cmp);

vector<pair<int, int> > v;

v.push_back(make_pair(arr[0].first, arr[0].second));

int cnt = 1;

for(int i=1; i<N; i++){

bool flag = false;

for(int j=0; j<v.size(); j++){

if(arr[i].first <= v[j].second){

flag = true;

if(v[j].first < arr[i].first) v[j].first = arr[i].first;

if(arr[i].second < v[j].second) v[j].second = arr[i].second;

}

}

if(!flag){

cnt++;

v.push_back(make_pair(arr[i].first, arr[i].second));

}

}

cout<<cnt<<"\n";

return 0;

}