Is it true that the army must use teleport? Or it can ignore teleport?

No comment =)
See the first sample - there is an answer to your question

No! In samples no answer!
In the first sample Katherina's army needs 8 days to arrive to Fortress, if it can ignore teleport, and 11 days, if it must use teleport. Or 10 days (using both B-teleport).
At the same time Gelu's army arrives to Fortress using teleport at 11 days.
Hence in this sample Katherina's army can come by several ways.

Oh, yes, now I see that you're right. It's an oversight of the author of the problem, of course. An army may not use teleports.

Finally! My code was accepted.
For future solutions: the number of teleports may be more than two.

There may be also 1 teleport, 2 teleports, 3 teleports,..

Edited by author 01.12.2011 00:24