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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
$input = trim(fgets(STDIN));
if ($input < 2 || $input > 10**5 || $input % 2 == 1) {
    exit(1);
}
$progression = trim(fgets(STDIN));
$list = explode(' ', $progression);
if ($input != count($list) ) {
    exit(1);
}
$len = count($list);
$error = 0;
for($i=0; $i<$len-2; $i++) {
    if($list[$i] == $list[$i+1]){
        $error++;
        if( $list[$i] == $list[$i+2]) {
            $error--;
        }
    } else if( $list[$i] != $list[$i+2]) {
        $error++;
    }
}
echo $error;