Your challenge is to create a regex that matches every string permutation of itself, and nothing else. The match must also be case-sensitive.

So, for example, if your regex is:

```
ABC

```

It should match (and only match) these strings:

```
ABC
ACB
BAC
BCA
CAB
CBA

```

It shouldn't match things like:

```
AABC (contains an extra A)
ABCD (contains an extra D)
AC   (no B)
AAA  (no B and C, extra 2 A's)
abc  (case-sensitive)

```

Rules:
------

* You are allowed to use any flavour of regex you like.
* Standard loopholes apply.
* You must have at least two different characters in your code. That means solutions like `1` are invalid.
* The regex should contain only printable ASCII, and nothing else.