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 C# (.NET Core 3.1.201) (judge verdict: Time Limit Exceeded)

using System;
using System.Collections.Generic;
using System.Linq;

namespace AtCoderCs
{

    class Program
    {

        const int Mod = 1000000007;

        static void Main()
        {

            var num = int.Parse(Console.ReadLine());
            const int alphabets = 'z' - 'a' + 1;
            var lists = new List<string>[alphabets, 10];
            for(int i = 0, j; i < alphabets; i++)
                for (j = 0; j < 10; j++) lists[i, j] = new List<string>();

            for (int i = 0; i < num; i++)
            {

                var str = Console.ReadLine();
                if (!lists[str[0] - 'a', str.Length - 1].Any(x => x == str)) lists[str[0] - 'a', str.Length - 1].Add(str);

            }

            int result = 0;
            for (int i = 0, j; i < alphabets; i++)
                for (j = 0; j < 10; j++) result += lists[i, j].Count;

            Console.WriteLine(result);

        }


    }
}