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: Accepted)

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

public class Program
{
    public void Proc()
    {
        int itemCount = int.Parse(Reader.ReadLine());
        int[] list = Reader.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();

        Dictionary<int, int> lst1 = new Dictionary<int, int>();
        Dictionary<int, int> lst2 = new Dictionary<int, int>();
        for (int i = 0; i < list.Length; i++) {

            if(i%2 == 0) {
                if(lst1.ContainsKey(list[i])) {
                    lst1[list[i]]++;
                } else {
                    lst1[list[i]] = 1;
                }

            } else {
                if (lst2.ContainsKey(list[i]))
                {
                    lst2[list[i]]++;
                }
                else
                {
                    lst2[list[i]] = 1;
                }
            }
        }
        int ans = 0;
        List<KeyValuePair<int, int>> l1 = lst1.OrderByDescending(a => a.Value).ToList();
        List<KeyValuePair<int, int>> l2 = lst2.OrderByDescending(a => a.Value).ToList();
        int tmp1 = l1.First().Value;
        if(l1.First().Key == l2.First().Key) {
            if(l2.Count > 1) {
                tmp1 += l2[1].Value;
            }
        } else {
            tmp1 += l2.First().Value;
        }
        int tmp2 = l2.First().Value;
        if (l2.First().Key == l1.First().Key)
        {
            if (l1.Count > 1)
            {
                tmp2 += l1[1].Value;
            }
        }
        else
        {
            tmp2 += l1.First().Value;
        }

        ans = itemCount - Math.Max(tmp1, tmp2);
        Console.WriteLine(ans);
    }




    public class Reader
    {
        static StringReader sr;
        public static bool IsDebug = false;
        public static string ReadLine()
        {
            if (IsDebug)
            {
                if (sr == null)
                {
                    sr = new StringReader(InputText.Trim());
                }
                return sr.ReadLine();
            }
            else
            {
                return Console.ReadLine();
            }
        }
        private static string InputText = @"

6
105 119 105 119 105 119


";
    }

    public static void Main(string[] args)
    {
#if DEBUG
        Reader.IsDebug = true;
#endif
        Program prg = new Program();
        prg.Proc();
    }
}