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 = readInputLine().toInt()
    
    val evenCnt = mutableMapOf<Int, Int>()
    val oddCnt = mutableMapOf<Int, Int>()
    
    val vs = readInputLine().split(" ").map{it.toInt()}
    
    for (i in 0 until n) {
        val num = vs[i]
        
        val useCnt = if (i % 2 == 0) oddCnt else evenCnt
        val cnt = useCnt.get(num) ?: 0
        useCnt.put(num, cnt + 1)
    }
    
    val evenList = evenCnt.toList().sortedByDescending{it.second}
    val oddList = oddCnt.toList().sortedByDescending{it.second}
    
    if (evenList.size == 1 && oddList.size == 1) {
        if (evenList.first().first != oddList.first().first) {
            println(0)
        } else {
            println(n / 2)
        }
    } else {
        if (evenList.first().first != oddList.first().first) {
            println(n - evenList.first().second - oddList.first().second)
        } else if (evenList.first().second < oddList.first().second) {
            println(n - evenList[1].second - oddList.first().second)
        } else {
            println(n - evenList.first().second - oddList[1].second)
        }
    }
}

fun readInputLine(): String {
    return readLine()!!
}