Employee Work Hours Monitoring

A company wants to implement a system to monitor its employees' check-in and check-out times to ensure compliance with working hours. Each employee uses a unique identification number, and may check in and out multiple times a day. The system should process three types of commands:

• LOG_IN employee_id day time: Record the check-in time (in minutes since midnight) for an employee on a given day.
• LOG_OUT employee_id day time: Record the check-out time (in minutes since midnight) for an employee on a given day.
• QUERY employee_id day: Calculate the total minutes worked by the employee on that day. Only complete check-in and check-out pairs (in order) should be counted. If there is an unmatched check-in or check-out, it is ignored.

For each QUERY command, output the total working minutes accumulated by properly pairing the check-ins with corresponding check-outs (i.e. pairing in their order of occurrence). If there are no valid pairs, return 0.

Note: All times are provided in minutes since midnight and days are represented as non-negative integers starting from 0.

Below is an example:

Input:
8
LOG_IN 101 0 540
LOG_OUT 101 0 600
LOG_IN 101 0 660
LOG_OUT 101 0 720
QUERY 101 0
LOG_IN 102 1 480
LOG_OUT 102 1 1020
QUERY 102 1
Output:
120
540

</p>

inputFormat

The first line contains an integer n representing the number of log entries. The following n lines each contain one of the three commands:

• LOG_IN employee_id day time
• LOG_OUT employee_id day time
• QUERY employee_id day

Here, employee_id, day, and time are integers. time is given in minutes since midnight.

outputFormat

For each QUERY command in the order they appear, output a line containing the total number of minutes worked by that employee on the specified day. Each result should be printed on a new line.

## sample

8
LOG_IN 101 0 540
LOG_OUT 101 0 600
LOG_IN 101 0 660
LOG_OUT 101 0 720
QUERY 101 0
LOG_IN 102 1 480
LOG_OUT 102 1 1020
QUERY 102 1

120
540

</p>