Shared code

/* 777 */
#include "bits/stdc++.h"
using namespace std;
 
#define int long long 
#define endl '\n'
#define all(x) x.begin(),x.end()
#define sortf(x) sort(all(x))
#define sortfn(x,fn) sort(all(x),fn)
#define sortr(x) sort(all(x),greater<int>())

using vi = vector <int>;
using vii = vector <vi>;
using viii = vector <vii>;
using pii = pair<int,int>;
using vpii = vector<pii>;

int res = 0;

void pre(){
 
}
 
void solve(){
	int n, x, y;cin >> n;
	vpii vec;
	while(n--) {
		cin >> x >> y;
		vec.emplace_back(x, y);
	}
	sortfn(vec,[&](pii a, pii b){
		if (a.second == b.second) return a.first > b.first;
		return a.second < b.second;
	});
	int cur = 0;
	for (auto& [st, end]: vec) {
		if (st >= cur) {
			cur = end;
			++res;
		}
	}
	cout << res << endl;
}
 
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	// pre();
	solve();
}