Redundant Friend Link Count

A social app processes m friend-link requests over n users (numbered 1 through n), in the given order. A request joining users u and v is called redundant if, at the moment it is processed, u and v are already in the same friend circle — that is, they are already connected directly or through a chain of earlier links (a request that links a user to themselves is also redundant). A non-redundant request adds a new link; a redundant request changes nothing.

Count how many of the m requests are redundant.

Input format

• Line 1: two integers n and m.
• Next m lines: two integers u and v (1-indexed), the request to link u and v, in processing order.

Output format

A single integer: the number of redundant requests.

Constraints

• 1 <= n <= 100000
• 0 <= m <= 200000
• 1 <= u, v <= n