LTS problem problem with the fsb code

Question

Hi this is ma code in the LTSA tool

 THREAD = (start-> RUNNABLE -> dead->THREAD),

 RUNNABLE = (yield ->RUNNABLE|NOT_RUNNABLE|THREAD),

 NOT_RUNNABLE = (RUNNABLE).

I get this error :

ERROR line:1 - ) expected

Anyone know to fix this

Many Thanks