In the game there is a 6 sided die which has 5 different faces (i.e. two of the faces are the same.) Considering that the die is fair and has 1/6 chance to roll any one side on each individual roll. What is the average number of rolls until I see the 5 different faces of the 6 sided die.

(I've seen a lot of different answers in regards to if each face of the die is different but not that pertains to if two sides have the same face. I'm sure it would change the formula significantly but I may be wrong.)

The above scenario is in the actual game. I'm trying to make my own scenario that is comparable. Thank you very much with your help.