Binge watching

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <cmath>

using namespace std;

using ll  = long long;
using vi  = vector<int>;
using vll = vector<long long>;
using vs  = vector<string>;
using pii = pair<int, int>;

#define all(x) (x).begin(), (x).end()
#define pb push_back
#define sz(x) ((int)(x).size())

using namespace std;

int main(){
  int n;
  cin >> n;
  vector<pii> hours(n);
  for(int i = 0; i < n; i++){
    int a, b;
    cin >> a >> b;
    hours[i] = {b,a};
  }
  sort(all(hours));

  int act_hour = 0, cont = 0;
  for(auto h : hours){
    int begining, end;
    begining = h.second;
    end = h.first;
    if(begining >= act_hour){
      act_hour = end;
      cont++;
    }
  }

  cout << cont << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED