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: Wrong Answer)

<?php
$n = trim(fgets(STDIN));

$input = trim(fgets(STDIN));
$ints = explode(' ', $input);

$nums = [];
foreach($ints as $i => $int) {
    $nums_solo[$int][] = true;

    $nums[$i%2][$int][] = true;
}

if(count($nums_solo) == 1) {
    echo $n/2;
    exit;
}
if(count($nums[0]) == 1 && count($nums[1]) == 1) {
    echo 0;
    exit;
}

uasort($nums[0], function($a, $b){
    return count($a) < count($b);
});
uasort($nums[1], function($a, $b){
    return count($a) < count($b);
});

if(key($nums[0]) == key($nums[1])) {
    $r1 = $n - (count($nums[0][0]) + count($nums[1][1]));
    $r2 = $n - (count($nums[0][1]) + count($nums[1][0]));
    echo $r1 < $r2 ? $r1 : $r2;
    exit;
}

if(key($nums[0][0]) == key($nums[1][0])) {
    $r1 = $n - (count($nums[0][0]) + count($nums[1][1]));
    $r2 = $n - (count($nums[0][1]) + count($nums[1][0]));
    echo $r1 < $r2 ? $r1 : $r2;
    exit;
}

echo $n - (count(array_shift($nums[0])) + count(array_shift($nums[1])));