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: Runtime Error)

import java.util.*;
public class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
  int n = sc.nextInt();
  int[] a = new int[n/2];
  int[] b = new int[n/2];
  int[] ac = new int[10001];
  int[] bc = new int[10001];
  for(int i = 0;i < n/2;i++){
    int p = sc.nextInt();
    a[i] = p;
    ac[p]++;
    int q = sc.nextInt();
    b[i] = q;
    bc[q]++;
  }
  int fa = 0;
  int sa = 0;
  int fb = 0;
  int sb = 0;
  int afk = 0;
  int ask = 0;
  int bfk = 0;
  int bsk = 0;
  for(int i = 1;i < 10001;i++) {
	  if(fa <= ac[i]) {
		  sa = fa;
		  fa = ac[i];
		  ask = afk;
		  afk = i;
	  }
	  if(fb <= bc[i]) {
         sb = fb;
		  fb = bc[i];
		  bsk = bfk;
		  bfk = i;
	  }
  }
  if(afk != bfk) {
	  System.out.println(n - fa - fb);
  }
  else {
	  int s = n - fa - sb;
	  int t = n - sa - fb;
	  System.out.println(s >= t ? t:s);

  }
}}