"It is not a problem."
Translation:Dyw hi ddim yn broblem.
Since it's a negative sentence it has to start with either 'dyw' or 'dydy'. Generally the female pronoun is used for 'it' if the sentence is not referring to a gendered noun, sometimes the male pronoun can be used for 'it' eg 'Y coffi! Dyw e ddim yn broblem' = The coffee, it is not a problem.