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 v = readLine()!!.split(" ").map { it.toInt() }
    if(v.all { it == v[0] }){
        println(n/2)
        return
    }

    val aOdd = mutableMapOf<Int, Int>()
    val aEven = mutableMapOf<Int, Int>()
    for(i in 1..n){
        val a = v[i-1]
        if(i % 2 == 0){
            if(aEven.containsKey(a)){
                aEven[a] = aEven[a]!! + 1
            }else{
                aEven[a] = 1
            }
        }
        if(i % 2 == 1){
            if(aOdd.containsKey(a)){
                aOdd[a] = aOdd[a]!! + 1
            }else{
                aOdd[a] = 1
            }
        }
    }

    val maxEven = if(aEven.keys.size == 1) n/2 else aEven.toList().maxBy { it.second }!!.first
    val maxOdd = if(aOdd.keys.size == 1) n/2 else aOdd.toList().maxBy { it.second }!!.first
    println(n - maxEven - maxOdd)
}