Handing out candies

You want to hand out candies to the participants of an algorithm camp.

You have $N$ candies, and every candy has a brand written as an integer.

First you decide $K$, the number of candies you hand out. Then you pick exactly one candy of each brand from brand $1$ through brand $K$.

$K$ can be any value from $1$ to $N$, and two candies of the same brand count as different candies. Write a program that computes the total number of ways to pick the candies, summed over every $K$.

The first line contains the number of candies $N$. ($1 \le N \le 50$)

The second line contains the brands of the $N$ candies, separated by spaces. Each brand is an integer between $1$ and $50$.

Print the number of ways to pick the candies on the first line. The value is smaller than $2^{31}$.