Propositional logic, inference rule, need explanation symbol |-

Question

Hi I am trying to do my homework. I need to say if the sequents are valid or not.

my biggest problem is I don't know what the sign |- means.

I don't need an answer for the problems but just an explanation for the symbol |-

examples of my problem is:

1. (p->q),q |- p

2. |- (p -> q)->(Not q -> Not p)

Thank you for the help!