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.Linq ;　

class C
{
  static void  Main (string[] args)
  {
    Console.ReadLine ();
     var vals = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
    var odd = vals.Where ((p,i)=>i%2!=0).GroupBy(p=>p).OrderBy(p=>-p.Count()).ToArray();
    var evn = vals.Where ((p,i)=>i%2==0).GroupBy(p=>p).OrderBy(p=>-p.Count()).ToArray();
if(odd[0].Key != evn[0].Key) Console.WriteLine(vals.Length -(odd[0].Count()+evn[0].Count()));
else Console.WriteLine(vals.Length - Math.Max(odd[0].Count()+(evn.Skip(1).FirstOrDefault()?.Count()??0), evn[0].Count()+(odd.Skip(1).FirstOrDefault()?.Count()??0)));
  }
}