Matrix-Cache 366/81 (Challenge Cache) Mystery Cache
Matrix-Cache 366/81 (Challenge Cache)
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Difficulty:
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Terrain:
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Size:
 (micro)
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Matrix-Cache 366/81 (Challenge Cache)
It's simple to understand but not so easy to do.. 
Please feel free to log this challenge cache
if your 366 matrix and your 81 matrix are completely filled!
There are no other tasks, all cache types are valid.

And where you can find the little cache container?
Please answer a simple question to calculate final coordinates:
How many caches (A) you have to find at least to fulfill these requirements?
The cache location is at:
N 51° 03.(538-A) E 013° 44.(389+A)

Please add any log permission to your online log, logs without it will be deleted.
Enjoy the cache! 

Additional Hints
(Decrypt)
RA: frr fcbvyre