I got WA #11. Is there any special trick for this test?

Or maybe my algo is incorrect.

The second minimal tree is diferrent from the first one by one edge. That's the main idea.

When you solve an optimization problem first of all you
must guarantee not missing any candidates to solution but
don’t depend on good luck. So I think and have Ac 1416 that you must sequentially one by one cut each edge of the first tree and find first tree in residue graph. Best such tree- is answer.