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));
$array = explode(" ", trim(fgets(STDIN)));
for($i = 0; $i < $n; $i++){
    @$map[$i % 2][$array[$i]]++;
}
if(maxKey($map[0]) != maxKey($map[1])){
    echo $n - max($map[0]) - max($map[1]);    
}else{
    //map[0]のMaxを採用する場合
    for($i = 0; $i < 2; $i++){    
        $map0 = $map[$i % 2];
        $map1 = $map[($i + 1) % 2];
        rsort($map0);
        rsort($map1);
        array_shift($map0);
        $num[] = $n - array_shift($map0) - array_shift($map1);
    }
    echo min($num);
}
function maxKey($array){
    $max = max($array);
    foreach($array as $key => $value){
        if($value == $max)return $key;
    }
}