Problem:
Score : 200 points

Problem Statement

An X-layered kagami mochi (X ≥ 1) is a pile of X round mochi (rice cake) stacked vertically where each mochi (except the bottom one) has a smaller diameter than that of the mochi directly below it. For example, if you stack three mochi with diameters of 10, 8 and 6 centimeters from bottom to top in this order, you have a 3-layered kagami mochi; if you put just one mochi, you have a 1-layered kagami mochi.

Lunlun the dachshund has N round mochi, and the diameter of the i-th mochi is d_i centimeters. When we make a kagami mochi using some or all of them, at most how many layers can our kagami mochi have?

Constraints

1 ≤ N ≤ 100

1 ≤ d_i ≤ 100

All input values are integers.

Input

Input is given from Standard Input in the following format:

N
d_1
:
d_N

Output

Print the maximum number of layers in a kagami mochi that can be made.

Sample Input 1

4
10
8
8
6

Sample Output 1

3

If we stack the mochi with diameters of 10, 8 and 6 centimeters from bottom to top in this order, we have a 3-layered kagami mochi, which is the maximum number of layers.

Sample Input 2

3
15
15
15

Sample Output 2

1

When all the mochi have the same diameter, we can only have a 1-layered kagami mochi.

Sample Input 3

7
50
30
50
100
50
80
30

Sample Output 3

4

Solution in OCaml (4.02.3) (judge verdict: Accepted)

let input () =
    let n  = int_of_string (read_line ())
    in let rec ds i result = if i >= n
        then result
        else let input = int_of_string (read_line ())
             in  ds (i+1) (input::result)
    in List.rev (ds 0 [])

let remove_duplicate (x::xs) = 
    let rec remove_duplicate' prev l = 
        match l with
        | []    -> []
        | x::xs -> if x == prev 
            then remove_duplicate' x xs
            else x :: (remove_duplicate' x xs)
    in x :: (remove_duplicate' x xs)

let _ = List.sort (Pervasives.compare) (input ())
     |> remove_duplicate
     |> List.length 
     |> print_int 
     |> print_newline