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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php
  
$n = trim(fgets(STDIN));
$a = explode(' ', trim(fgets(STDIN)));
 
$e = $o = [];
for($i=0; $i<$n; $i++){
  if ($i%2 ==0) array_push($e, $a[$i]);
  if ($i%2 ==1) array_push($o, $a[$i]);
}
 
$ec = array_count_values($e);
$oc = array_count_values($o);
 
$ek = array_keys($ec, max($ec));
$ok = array_keys($oc, max($oc));
 
$au = array_unique($a);
if (count($au) == 1){
  echo $n/2;
} else if ($ek !== $ok){
  echo $n - max($ec) - max($oc);
} else {
  rsort($ec);
  rsort($oc);
  echo $n - max($ec[0] + $oc[1], $oc[0] + $ec[1]);
}
 
 
?>