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 (
	"fmt"
)

func main() {
	var n int
	fmt.Scanf("%d", &n)
	evc, ovc := make(map[int]int), make(map[int]int)
	for i := 0; i < n/2; i++ {
		var v int
		fmt.Scanf("%d", &v)
		evc[v]++
		fmt.Scanf("%d", &v)
		ovc[v]++
	}
	if len(evc) == 1 && len(ovc) == 1 {
		var v int
		for v, _ = range evc {
			break
		}
		if ovc[v] > 0 {
			fmt.Printf("%d\n", n/2)
			return
		}
	}
	evm, ovm := 0, 0
	for _, vc := range evc {
		if vc > evm {
			evm = vc
		}
	}
	for _, vc := range ovc {
		if vc > ovm {
			ovm = vc
		}
	}
	fmt.Printf("%d\n", n-evm-ovm)
}