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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

fun main(args: Array<String>) {
    val n = readLine()!!.toInt()
    val l = readLine()!!.split(" ").map { it.toInt() }
    var slash = mutableListOf<Int>()
    var backslash = mutableListOf<Int>()
    for(i in 0 until n){
        if (i % 2 == 0) slash.add(l[i])
        else backslash.add(l[i])
    }
    val slashmap = slash.groupBy { it }.mapValues { it.value.count() }
    val backslashmap = backslash.groupBy { it }.mapValues { it.value.count() }
    val slashcounts = slashmap.values.take(2)
    val backslashconuts = backslashmap.values.take(2)
    if (slashmap == backslashmap) println(n / 2)
    else println(Math.min(n - (slashcounts.first() + backslashconuts.last()) ,n - (slashcounts.last() + backslashconuts.first())))
}