Problem:
Score : 300 points

Problem Statement

A sequence a_1,a_2,... ,a_n is said to be /\/\/\/ when the following conditions are satisfied:

For each i = 1,2,..., n-2, a_i = a_{i+2}.

Exactly two different numbers appear in the sequence.

You are given a sequence v_1,v_2,...,v_n whose length is even.
We would like to make this sequence /\/\/\/ by replacing some of its elements.
Find the minimum number of elements that needs to be replaced.

Constraints

2 \leq n \leq 10^5

n is even.

1 \leq v_i \leq 10^5

v_i is an integer.

Input

Input is given from Standard Input in the following format:

n
v_1 v_2 ... v_n

Output

Print the minimum number of elements that needs to be replaced.

Sample Input 1

4
3 1 3 2

Sample Output 1

1

The sequence 3,1,3,2 is not /\/\/\/, but we can make it /\/\/\/ by replacing one of its elements: for example, replace the fourth element to make it 3,1,3,1.

Sample Input 2

6
105 119 105 119 105 119

Sample Output 2

0

The sequence 105,119,105,119,105,119 is /\/\/\/.

Sample Input 3

4
1 1 1 1

Sample Output 3

2

The elements of the sequence 1,1,1,1 are all the same, so it is not /\/\/\/.

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

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

namespace ARC103_A
{
    class Program
    {
        static void Main(string[] args)
        {
            string n = Console.ReadLine();
            string[] inputs = Console.ReadLine().Split(' ');
            var dic = new Dictionary<string, int>();

            foreach(string s in inputs)
            {
                if (dic.Keys.Contains(s))
                {
                    dic[s] += 1;
                }
                else
                {
                    dic[s] = 1;
                }
            }
            var sDic = dic.OrderByDescending(x => x.Value);

            int count = 0;
            if (sDic.Count() == 1)
            {
                count = sDic.First().Value / 2;
            }
            else
            {
                int i = 0;
                foreach (var item in sDic)
                {
                    if (i >= 2)
                    {
                        count += item.Value;
                    }
                    i++;
                }
            }
            //System.Diagnostics.Debug.WriteLine(count);
            Console.WriteLine(count);
        }
    }
}