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 Perl (v5.18.2) (judge verdict: Wrong Answer)

chomp($n=<>);
chomp($a=<>);
@ary=split/ /,$a;

for($i=0;$i<$n;$i++){
    if($i%2==0){
        push @even,$ary[$i];
    } else{
        push @odd,$ary[$i];
    }
}

%hashe=();
foreach (@even){
    $hashe{$_}++;
}
$num=0;
$num2=0;
foreach (sort {$hashe{$b} <=> $hashe{$a}} keys %hashe){
    if($num==0){
        $num=$hashe{$_};
        $tope=$_;
    }elsif($num2==0){
        $num2=$hashe{$_};
    }
}
$cnt = @even - $num;
$cnt2 = @even - $num2;
%hasho=();
foreach (@odd){
    $hasho{$_}++;
}
$num=0;
$num2=0;
foreach (sort {$hasho{$b} <=> $hasho{$a}} keys %hasho){
    if($num==0){
        $num=$hasho{$_};
        $topo=$_;
    }elsif($num2==0){
        $num2=$hasho{$_};
    }
}
if($tope == $topo){
    $cnt+= @odd - $num2;
    $cnt2+=@odd - $num;
    if($cnt <= $cnt2){
        $ans = $cnt;
    }else{
        $ans = $cnt2;
    }
}
$cnt+= @odd - $num;
$ans =$cnt;
print $ans;