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

namespace PastQuestions
{
    class Program
    {
        static void Main(string[] args)
        {
            new Program().Solve(new Input(Console.In));
        }

        public void Solve(Input input)
        {
            var n = input.ReadInt;
            List<int> d = new List<int>();
            for (var i = 0; i < n; ++i)
            {
                d.Add(input.ReadInt);
            }

            Console.WriteLine(d.Distinct().ToArray().Length);
        }
    }

    public class Input
    {
        private TextReader Stream { get; }
        private char Separator { get; }
        private Queue<string> InputStream { get; }

        public Input(TextReader stream, char separator = ' ')
        {
            Stream = stream;
            Separator = separator;
            InputStream = new Queue<string>();
        }

        public string Read
        {
            get
            {
                if (InputStream.Count != 0) return InputStream.Dequeue();
                string[] tmp = Stream.ReadLine().Split(Separator);
                for (int i = 0; i < tmp.Length; ++i)
                    InputStream.Enqueue(tmp[i]);
                return InputStream.Dequeue();
            }
        }

        public string ReadLine => Stream.ReadLine();
        public int ReadInt => int.Parse(Read);
        public long ReadLong => long.Parse(Read);
        public double ReadDouble => double.Parse(Read);
        public int[] ReadIntArray => Stream.ReadLine().Split(Separator).Select(i => int.Parse(i)).ToArray();
        public long[] ReadLongArray => Stream.ReadLine().Split(Separator).Select(l => long.Parse(l)).ToArray();
    }
}