Научная конференция

#define _USE_MATH_DEFINES
#include <iostream>
#include <conio.h>
#include <string>
#include <set>
#include <map>
#include <algorithm>
#include <string>
#include <math.h>
#include <vector>
#include <cmath>
#include <sstream>

using namespace std;

struct time
{
    long long end, start;
};

bool operator<(time p1, time p2)
{
    if (p1.end == p2.end)
        return p1.start < p2.start;
    else
        return p1.end < p2.end;
}

int main()
{
    vector<time> times;
    long long prom1, prom2, n, sc = 1;

    cin >> n;

    for (int i = 1; i <= n; i++)
    {
        time prom;
        cin >> prom1 >> prom2;
        prom.start = prom1;
        prom.end = prom2;
        times.push_back(prom);
    }

    sort(times.begin(), times.end());

    prom1 = times[0].end;

    for (int i = 1; i < n; i++)
    {
        if (prom1 < times[i].start)
        {
            prom1 = times[i].end;
            sc++;
        }
    }

    cout << sc;
    _getch();
    return 0;
}