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.Text;
using System.Collections.Generic;
using static System.Math;
using System.Linq;
using static System.Array;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = long.Parse(Console.ReadLine());
            var A = Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToArray();


            var dic1 = new Dictionary<long,long>();
            var dic2 = new Dictionary<long,long>();
            dic1.Add(-1, 0);
            dic2.Add(-1, 0);
            for (int i = 0; i < N; i++)
            {
                var now = A[i];

                if (i%2 == 0)
                {
                    if (dic1.ContainsKey(now))
                    {
                        dic1[now]++;
                    }
                    else
                    {
                        dic1.Add(now, 1);
                    }
                }
                else
                {
                    if (dic2.ContainsKey(now))
                    {
                        dic2[now]++;
                    }
                    else
                    {
                        dic2.Add(now, 1);
                    }
                }
            }


            var dic1max1 = -1L;
            var dic1val1 = 0L;
            var dic1max2 = -1L;
            var dic1val2 = 0L;

            foreach (var item in dic1)
            {
                if(item.Value > dic1val1)
                {
                    dic1max2 = dic1max1;
                    dic1val2 = dic1val1;
                    dic1max1 = item.Key;
                    dic1val1 = item.Value;
                }
                else if(item.Value > dic1val2)
                {
                    dic1max2 = item.Key;
                    dic1val2 = item.Value;
                }
            }

            var dic2max1 = -1L;
            var dic2val1 = 0L;
            var dic2max2 = -1L;
            var dic2val2 = 0L;

            foreach (var item in dic2)
            {
                if (item.Value > dic2val1)
                {
                    dic2max2 = dic2max1;
                    dic2val2 = dic2val1;
                    dic2max1 = item.Key;
                    dic2val1 = item.Value;
                }
                else if (item.Value > dic2val2)
                {
                    dic2max2 = item.Key;
                    dic2val2 = item.Value;
                }
            }

            if(dic1max1 != dic2max1)
            {
                Console.WriteLine(N -dic1val1 - dic2val1);
            }
            else
            {

                Console.WriteLine(Min(N - dic1val1 - dic2val2,N - dic1val2 - dic2val1));
            }

            
        }


    }

}