Usable Laptops

You are given two lists of laptop IDs. The first list contains the IDs of available laptops and the second list contains the IDs of broken laptops. A laptop is considered usable if it appears in the available list and does not appear in the broken list. Mathematically, the number of usable laptops is given by:

\( U = \left|\{ x \in Available \mid x \notin Broken \}\right|\)

Read the input from standard input (stdin) and output the result to standard output (stdout).

inputFormat

The input is read from stdin and consists of four lines:

• The first line contains an integer n representing the number of available laptops.
• The second line contains n space-separated strings representing the IDs of available laptops.
• The third line contains an integer m representing the number of broken laptops.
• The fourth line contains m space-separated strings representing the IDs of broken laptops.

outputFormat

Output a single integer, which is the count of usable laptops.

3
L1 L2 L3
2
L4 L5

3