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

class MainClass
{
    public static long Read()
    {
        return long.Parse(Console.ReadLine());
    }

    public static long[] Reads()
    {
        return Console.ReadLine().Split().Select(long.Parse).ToArray();
    }

    public static long GCD(long a,long b)
    {
        if (a < b)
            GCD(b, a);
        while (b != 0)
        {
            long r=a % b;
            a = b;
            b = r;
        }
        return a;
    }
    public static void Main(string[] args)
    {
        var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
        Console.SetOut(sw);
        var n = Read();
        var vo = new long[n / 2];
        var ve = new long[n / 2];
        var input = Reads();
        for(int i = 0; i < n/2; i++)
        {
            ve[i] = input[2 * i];
            vo[i] = input[2 * i + 1];
        }
        
        Array.Sort(vo);
        Array.Sort(ve);
        
        int counto = 0;
        int tmpcounto = 1;
        int counte = 0;
        int tmpcounte = 1;
        bool b = true;
        for (int i = 0; i < n / 2 - 1; i++)
        {
            if (vo[i] != vo[i + 1])
            {
                b = false;
                if (counto < tmpcounto)
                    counto = tmpcounto;
                tmpcounto = 1;
            }
            else
            {
                tmpcounto++;
                b = true;
            }
             
        }
        if (b)
            counto = tmpcounto;
        b = true;
        for (int i = 0; i < n / 2 - 1; i++)
        {
            if (ve[i] != ve[i + 1])
            {
                b = false;
                if (counte < tmpcounte)
                    counte = tmpcounte;
                tmpcounte = 1;
            }
            else
            {
                b = true;
                tmpcounte++;
            }
        }
        if (b)
            counte = tmpcounte;
        var answer = n - counto - counte;
        if (answer == 0 && (vo[0] == ve[0]))
            Console.WriteLine(n / 2);
        else
            Console.WriteLine(answer);
       


        Console.Out.Flush();
    }
}