Problem:
Score : 300 points

Problem Statement

You drew lottery N times. In the i-th draw, you got an item of the kind represented by a string S_i.

How many kinds of items did you get?

Constraints

1 \leq N \leq 2\times 10^5

S_i consists of lowercase English letters and has a length between 1 and 10 (inclusive).

Input

Input is given from Standard Input in the following format:

N
S_1
:
S_N

Output

Print the number of kinds of items you got.

Sample Input 1

3
apple
orange
apple

Sample Output 1

2

You got two kinds of items: apple and orange.

Sample Input 2

5
grape
grape
grape
grape
grape

Sample Output 2

1

Sample Input 3

4
aaaa
a
aaa
aa

Sample Output 3

4

Solution in OCaml (4.10.0) (judge verdict: Accepted)

module SS = Set.Make(String);;
let () =
  let n = read_int () in
  let s = Array.to_list (Array.init n @@ fun _ -> Scanf.scanf "%s\n" @@ fun s -> s) in
  let ans = List.fold_right SS.add s (SS.empty) in
  print_int (SS.cardinal ans)