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.Numerics;
using System.Linq;
using System.Collections.Generic;
using System.Text;

namespace debug
{
    class ProgramC
    {
        static void Main(string[] args)
        {

            //入力
            int n = int.Parse(Console.ReadLine());
            string[] s = Console.ReadLine().Split(' ');
            int[] odd = new int[100000];
            int[] even = new int[100000];

            for (int i = 0; i < n; i++)
            {
                if (i % 2 == 0)
                {
                    odd[int.Parse(s[i]) - 1]++;
                    continue;
                }

                even[int.Parse(s[i]) - 1]++;

            }

            int em = 0;
            int ec = 0;
            int om = 0;
            int oc = 0;

            for (int i = 0; i < 100000; i++)
            {
                int temp1 = even[i];
                int temp2 = odd[i];

                if (ec < temp1)
                {
                    em = i;
                    ec = temp1;
                }
                if (oc < temp2)
                {
                    om = i;
                    oc = temp2;
                }

            }

            if(em == om)
            {
                if(odd.Max() > even.Max())
                    Console.WriteLine(n - odd.Max());
                else
                    Console.WriteLine(n - even.Max());
                return;
            }
             
            
            Console.WriteLine(n - odd.Max() - even.Max());
            

        }

        
    }

    

}