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 Go (1.6) (judge verdict: Wrong Answer)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

var v []int
var n int

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	v = make([]int, n)
	m1 := make(map[int]int)
	m2 := make(map[int]int)

	for i := 0; i < n; i++ {
		v[i] = nextInt()
		if i%2 == 0 {
			m1[v[i]]++
		} else {
			m2[v[i]]++
		}
	}

	if len(m1) == 1 && len(m2) == 1 {
		flag := true

		for i := 0; i < n-1; i++ {
			if v[i] != v[i+1] {
				flag = false
				break
			}
		}

		if flag {
			fmt.Println(n / 2)
			return
		}
	}

	// fmt.Println(m1)
	// fmt.Println(m2)

	em := 0
	for _, v := range m1 {
		if em < v {
			em = v
		}
	}

	om := 0
	for _, v := range m2 {
		if om < v {
			om = v
		}
	}

	ans := n - em - om
	fmt.Println(ans)
}