# Is the language Sol decidable or not?

I define the language Sol as a turing machine M with alphabet{s,o,l} and we want to decide if sol $$\in$$ L(M).

Is this decidable? How can I prove it? It seems that three case could occur either sol $$\in L(M)$$ or sol $$\notin$$ L(M) or the Turing machine M would loop. Is trying to use mapping reducibility with the language $$A_{TM}$$ defined as a Tm M that accepts w a good idea? If possible this would prove that Sol is undecidable because $$A_{TM}$$ undecidable.