Elmo makes $N$ cupcakes for a school bake sale. For each cupcake, he uses $B$ scoops of flour at $5$ cent per scoop and $J$ scoops of sugar at $8$ cent per scoop. The total cost of the flour and sugar to make all the cupcakes is $\$3.91$. Assume that $B,J,N$ are positive integers with $N>1$. What is the cost of the sugar Elmo uses to make the cupcakes?