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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

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

class Program
{
    static void Main(string[] args)
    {
        var io = new StandardIO();
        new Process(io).Run();
    }

}

class Process
{
    public Process(IIO io)
    {
        this.io = io;
    }

    IIO io;

    public void Run()
    {
        var count = io.GetInteger();
        int[] ds = new int[count];
        for (int i = 0; i < count; i++)
            ds[i] = io.GetInteger();
        var result = ds.Distinct().Count();
        io.Write(result.ToString());
    }
}

public interface IIO
{
    string Get();
    void Write(string s);
    void Flush();
}

public class StandardIO : IIO
{
    string IIO.Get()
    {
        return Console.ReadLine();
    }

    void IIO.Write(string s)
    {
        Console.WriteLine(s);
    }

    void IIO.Flush()
    {
        Console.Out.Flush();
    }
}

public static class InputExtension
{
    public static int GetInteger(this IIO input)
    {
        return int.Parse(input.Get());
    }

    public static string[] GetStrings(this IIO input, char separator = ' ')
    {
        return input.Get().Split(separator);
    }

    public static int[] GetIntegerArray(this IIO input, char separator = ' ')
    {
        return input.GetStrings().Select(s => int.Parse(s)).ToArray();
    }
}