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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
import java.io.*;

public class Main
{
    public static void main (String [] args) throws Exception
    {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int n = sc.nextInt() ;
        int [] a = new int[n] ;

        TreeMap<Integer,Integer> map1 = new TreeMap<>();
        TreeMap<Integer,Integer> map2 = new TreeMap<>();

        for(int i = 0 ;i < n ;i++) {
            a[i] = sc.nextInt();
            if((i & 1) == 0)
                map1.put(a[i], map1.getOrDefault(a[i] , 0) + 1) ;
            else
                map2.put(a[i], map2.getOrDefault(a[i] , 0) + 1) ;
        }

        int min1 = (1 << 30) ;
        for(int x : map1.values())
            min1 = Math.min(min1 , x) ;

        if(min1 == n / 2) min1 = 0 ;

        int min2 = (1 << 30) ;
        for(int x : map2.values())
            min2 = Math.min(min2 , x) ;

        if(min2 == n / 2 && map1.firstKey().intValue() != map2.firstKey().intValue())
            min2 = 0 ;

        out.print(min1+min2);
        out.flush();
        out.close();
    }

    static class Scanner
    {
        BufferedReader br;
        StringTokenizer st;

        Scanner(InputStream in)
        {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() throws Exception
        {
            while (st == null || !st.hasMoreTokens())
                st = new StringTokenizer(br.readLine());
            return st.nextToken();
        }

        int nextInt() throws Exception { return Integer.parseInt(next()); }

        long nextLong() throws Exception { return Long.parseLong(next()); }

        double nextDouble() throws Exception { return Double.parseDouble(next());}
    }

    static void shuffle(int [] a)
    {
        int n =a.length ;

        for(int i = 0 ;i < n ; i++)
        {
            int r = i + (int)(Math.random() * (n - i)) ;
            int tmp = a[i] ;
            a[i] = a[r] ;
            a[r] = tmp ;
        }
    }

}