Extracting a part of string from Title of Song and rename title

Hello friends,
Here is situation I need to deal with:

Suppose the title of a song is:
abc - xyz
Now I need to extract 'abc' part of title and rename title as only 'abc'.

that is;
Old Title: abc - xyz
New Title: abc

In other words I need to delete the ' - xyz' part from old title.

And Please note that 'abc' part of song title is of variable length.

It would be of great relief if someone could help me to this task.

Create an action of the type "Guess value" for source %title%
Guessing pattern: %title% - %dummy%