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;
        using static System.Math;
        public class Program
        {
            public static void Main(string[] args)
            {
            int count = int.Parse(Console.ReadLine());
            List<int>  num = Console.ReadLine().Split(' ').Select(int.Parse).ToList();
            int answer = 0;

            if (num.Distinct().Count() == 1) answer = num.Count() / 2;
            else
            {
                if (num.Distinct().Count() == num.Count() - 1)
                {
                    answer = Abs(1 + num.GroupBy(x => x).Select(y => y.Count()).Max() - num.GroupBy(x => x).Select(y => y.Count()).Min());
                }
                if (num.Distinct().Count() == num.Count())
                {
                    answer = Abs(num.GroupBy(x => x).Select(y => y.Count()).Max() - num.GroupBy(x => x).Select(y => y.Count()).Min());
                }
                if(num.Distinct().Count() == num.Count())
                {
                    answer = num.Count() - 2;
                }
            }

            Console.WriteLine(answer);
            }
        }