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# (.NET Core 3.1.201) (judge verdict: Accepted)

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

namespace AtCoder.ABC
{
    class QuestionB
    {
        public static void Main(string[] args)
        {
            var n = int.Parse(Console.ReadLine());
            var v = Console.ReadLine().Split(" ").Select(x => int.Parse(x)).ToArray();

            var guusuu = new SortedDictionary<int, int>();
            var kisuu = new SortedDictionary<int, int>();

            for (int i = 0; i < n; i++) {
                if (i % 2 == 0) {
                    if (guusuu.ContainsKey(v[i]) == false) {
                        guusuu.Add(v[i], 0);
                    }

                    guusuu[v[i]]++;
                } else {
                    if (kisuu.ContainsKey(v[i]) == false) {
                        kisuu.Add(v[i], 0);
                    }

                    kisuu[v[i]]++;
                }
            }

            var guusuuList = guusuu.ToList();
            guusuuList.Sort((x, y) => y.Value.CompareTo(x.Value));

            var kisuuList = kisuu.ToList();
            kisuuList.Sort((x, y) => y.Value.CompareTo(x.Value));


            var guusuuMax = guusuuList.First();
            var kisuuMax = kisuuList.First();

            if (kisuuMax.Key != guusuuMax.Key) {
                Console.WriteLine(n - kisuuMax.Value - guusuuMax.Value);
            } else {
                var guusuuMax2 = new KeyValuePair<int, int>(0, 0);

                if (guusuuList.Count >= 2) {
                    guusuuMax2 = guusuuList[1];
                }

                var kisuuMax2 = new KeyValuePair<int, int>(0, 0);

                if (kisuuList.Count >= 2) {
                    kisuuMax2 = kisuuList[1];
                }

                var min = n - guusuuMax.Value - kisuuMax2.Value;

                min = Math.Min(n - guusuuMax2.Value - kisuuMax.Value, min);

                Console.WriteLine(min);
            }
        }
    }
}