DAPC21-046.`git mv`

During development, you recently moved a file from one location to another. To keep your development team up to date with the change you made, you want to send them a short description of the change, without making use of any versioning software.

Both the source location and destination are valid Unix path names, that is, a nonempty string consisting of lowercase letters and “/” such that no “/” occurs at the begin or the end, nor does it contain two consecutive forward slashes.

You need to find the shortest string of the form “A{B => C}D” such that:

• The source location is “ABD” and the destination is “ACD”, where double forward slashes should be read as one forward slash. For example, if a file is moved from “a/c” to “a/b/c”, we can describe this movement by “a/{ => b}/c”, meaning the source location was “a/c” and not “a//c”.

• The string $A$ is empty or ends with a forward slash, and similarly $D$ is empty or starts with a forward slash.

• Both $B$ and $C$ do not start or end with a forward slash.