CD

Sang-geun and Seon-yeong each own a collection of CDs, and they want to sell the CDs that both of them own. How many CDs do the two of them own in common?

The input consists of several test cases. The first line of each test case contains the number of CDs $N$ that Sang-geun owns and the number of CDs $M$ that Seon-yeong owns. $N$ and $M$ are at most $1{,}000{,}000$. The next $N$ lines each contain one of Sang-geun's CD numbers in ascending order, one per line, and the following $M$ lines each contain one of Seon-yeong's CD numbers in ascending order, one per line. Every CD number is a positive integer no greater than $1{,}000{,}000{,}000$. No person owns two CDs with the same number. The last line of the input is 0 0 and must not be processed.

For each test case, print on its own line the number of CDs that both of them own.