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: Time Limit Exceeded)

fun main(args: Array<String>) {
    val n = readLine()!!.toInt()
    val v = readLine()!!.split(" ").map(String::toInt)

    val odds = v.filterIndexed { i, e -> i % 2 == 1 }.groupBy { it }.mapValues { it.value.size }
    val evens = v.filterIndexed { i, e -> i % 2 == 0 }.groupBy { it }.mapValues { it.value.size }

    val half = n / 2
    var min = Integer.MAX_VALUE

    for ((oddNum, oddSize) in odds) {
        for ((evenNum, evenSize) in evens) {
            if (oddNum == evenNum) {
                continue
            }
            min = Math.min(min, half - oddSize + half - evenSize)
        }
    }

    if(min == Integer.MAX_VALUE){
        min = half
    }

    println(min)
}