Pat class A - check in and check out

Check in and check out

The first person to the computer room is responsible for opening the door every day , The last person to leave the machine room is responsible for locking the door .

Now? , Give everyone's check-in and check-out records , Please find out who opened the door that day and who locked the door .

Input format

The first line contains integers MM, Expressing common ownership MM Personal check-in and check-out records .

Next MM That's ok , The form of each line is as follows ：

ID_number Sign_in_time Sign_out_time

Time to HH:MM:SS Form gives ,ID_number Is a length not more than 1515 String .

Output format

All in one line , Output the of the door opener and the door locker ID_number, Separated by a space .

Data range

1≤M≤101≤M≤10,
The data ensures that everyone's check-in time is earlier than the check-out time , And there will be no two people signing in or checking out at the same time .

sample input ：

3
CS301111 15:30:28 17:00:10
SC3021234 08:00:00 11:25:25
CS301133 21:45:00 21:58:40

sample output ：

SC3021234 CS301133

#include <bits/stdc++.h>

using namespace std;

int main()
{
    string op_id, op_time;
    string cl_id, cl_time;
    
    int n;
    cin >> n;
    
    for(int i = 0; i < n; i ++)
    {
        string id, in_time, out_time;
        cin >> id >> in_time >> out_time;
        if(!i || in_time < op_time)
        {
            op_id = id;
            op_time = in_time;
        }
        if(!i || out_time > cl_time)
        {
            cl_id = id;
            cl_time = out_time;
        }
    }
    
    cout << op_id << " " << cl_id << endl;
    
    return 0;
}