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: Time Limit Exceeded)

package main

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

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ := strconv.Atoi(scanner.Text())
	v := make([]int, n)
	for i := 0; i < n; i++ {
		scanner.Scan()
		v[i], _ = strconv.Atoi(scanner.Text())
	}

	lvals := map[int]int{}
	for i := 0; i < n; i += 2 {
		lvals[v[i]] += 1
	}
	rvals := map[int]int{}
	for i := 1; i < n; i += 2 {
		rvals[v[i]] += 1
	}

	max := 0

	for lk, lv := range lvals {
		for rk, rv := range rvals {
			if lk == rk {
				continue
			}
			if max < lv+rv {
				max = lv + rv
			}
		}
	}

	if max == 0 {
		max = n / 2
	}

	fmt.Println(n - max)
}