# [Husk], <s>14</s> 13 bytes
-1 byte thanks to [Dominic van Essen](https://codegolf.stackexchange.com/users/95126/dominic-van-essen)

    ◄§-▼▲fo=▲¹Σπ3

[Try it online!][TIO-kxq69g2g]

### Explanation

    ◄§-▼▲fo=▲¹Σπ3
               π3     cartesian product of 3 * input
         fo          filter by composed function
           =▲¹Σ      max of input equals sum
    ◄§               min by composed binary function
      -▼▲            max - min


[Husk]: https://github.com/barbuz/Husk
[TIO-kxq69g2g]: https://tio.run/##yygtzv7//9H0lkPLdR9N2/No2qa0fFsgeWjnucXnG4z///8fbahjpGOsY6JjqmOmY65joWOpY2gQCwA "Husk – Try It Online"