Two collections#2243
Twins Sasha and Pasha are avid stamp collectors, each maintaining their own collection. They strive to keep their collections equal in size, so both collections always contain the same number of stamps. This balance can be difficult to maintain, since Sasha or Pasha may sometimes buy stamps they already own. For example, if Pasha acquires a new rare stamp, what should Sasha do? It can be impossible to find a second such stamp, or too hard to acquire a different rarity... So they might buy the first available one they see!
It is interesting to find out how many unique stamps are common between Pasha's and Sasha's collections. Only distinct stamp indices should be considered. Write a program to determine this number.
The first line contains a single integer — the number of stamps in each collection. The next two lines each contain integers, the indices of the stamps in Pasha's and Sasha's collections, respectively. All indices are positive integers not greater than . It is guaranteed that N \leq 10000.
Output the number of unique stamp indices found in both collections.
Example 1