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;

class Code{
	static void Main(string[] args){
    	Method(args);
        Console.WriteLine();
    }
    
    static void Method(string[] args){
        int n=int.Parse(Console.ReadLine());
        var vs = new int[n];
        string[] s=Console.ReadLine().Split(' ');
        for(int i=0;i<n;i++){
        	vs[i] = int.Parse(s[i]);
        }
      
    	var evens = new int[100000];
    	var odds = new int[100000];
      	for(int i=0;i<n;i++){
          if(i%2==0){
            odds[vs[i]-1]++;
          }
          else{
            evens[vs[i]-1]++;            
          }
        }
      int evenMax=-1,evenSub=0;
      int oddMax=-1,oddSub=0;
      if(evens[0]<evens[1]){
        evenMax=1;
        evenSub=0;
      }
      else{
        evenMax=0;
        evenSub=1;
      }
      if(odds[0]<odds[1]){
        oddMax=1;
        oddSub=0;
      }
      else{
        oddMax=0;
        oddSub=1;
      }
      
      for(int i=0;i<100000;i++){
        if(evenMax == -1 || evens[evenMax]<evens[i]){
          evenSub=evenMax;
          evenMax = i;
        }
        if(oddMax == -1 || odds[oddMax]<odds[i]){
          oddSub=oddMax;
          oddMax = i;
        }
      }
      /*Console.WriteLine(evenMax);
      Console.WriteLine(evenSub);
      Console.WriteLine(oddMax);
      Console.WriteLine(oddSub);*/
      if(evenMax!=oddMax){
        Console.WriteLine(n-evens[evenMax]-odds[oddMax]);
      }
      else{
        if(evenMax+oddSub<evenSub+oddMax){
          Console.WriteLine(n-evens[evenSub]-odds[oddMax]);
        }
        else{
          Console.WriteLine(n-evens[evenMax]-odds[oddSub]);          
        }
      }
    }
}