Let Ü replace the triplet AAU in one of its permutations. There are 4!=24 ways to rearrange letters B, C, S, Ü. In each of those, there are 3 different variants of Ü, as it can be UAA, AUA and AAU. Hence, it's 3 times 24, 72 ways.
OK, seems like this is the solution you already have. Let's see what can we do about it.
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A (x2)
B
C
U
S
