Warehouse Stock Management

This problem involves managing stock levels in a warehouse by processing various commands. You are given a series of commands to update or query the stock level of products. The commands are as follows:

• ADD product_id quantity: Add a specified quantity of the product to the warehouse.
• REMOVE product_id quantity: Remove a specified quantity from the warehouse, ensuring that the stock does not fall below zero.
• TRANSFER product_id quantity location: Transfer a specified quantity of the product to a different location. This command acts like a removal, reducing the stock.
• QUERY product_id: Output the current stock level of the specified product.

For a given sequence of commands, process each command in order. For every QUERY command, output the stock level on a new line.

Note: All quantities and product IDs are positive integers. The warehouse initially has a stock of 0 for every product.

In mathematical terms, if we denote the stock of a product i after a command as S(i), then for an addition command:

\[ S(i) = S(i) + q \]

For a removal or transfer command:

\[ S(i) = \max(0, S(i) - q) \]</p>

inputFormat

The input is given via standard input (stdin) and consists of:

1. An integer n on the first line, representing the number of commands.
2. Followed by n lines each containing one command.

Each command will be in one of the following forms: ADD product_id quantity, REMOVE product_id quantity, TRANSFER product_id quantity location, or QUERY product_id.

outputFormat

For each QUERY command, output the current stock level of the specified product on a new line.

## sample

4
ADD 1 100
ADD 2 150
QUERY 1
QUERY 2

100
150

</p>