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 Python (3.4.3) (judge verdict: Wrong Answer)

n = int(input())
str_num = input()
num = str_num.split()
even_num = {}
odd_num = {}

for index in range(0,n):
    if index%2 == 0:
        if num[index] in even_num:
            even_num[num[index]] += 1
        else:
            even_num[num[index]] = 1
    else:
        if num[index] in odd_num:
            odd_num[num[index]] += 1
        else:
            odd_num[num[index]] = 1

even_max_key = max(even_num, key=even_num.get)
odd_max_key = max(odd_num, key=odd_num.get)
even_change = int(n/2) - even_num[even_max_key]
odd_change = int(n/2) - odd_num[odd_max_key]

if even_max_key == odd_max_key:
	if even_change < odd_change:
		if len(even_num) == 1:
			odd_num = int(n/2)
		if len(even_num) != 1:
			del even_num[even_max_key]
			even_max_key = max(even_num, key=even_num.get)
			even_change = n/2 - even_num[even_max_key]
	else:
		if len(odd_num) == 1:
			even_change = int(n/2)
		if len(odd_num) != 1:
			del odd_num[odd_max_key]
			odd_max_key = max(odd_num, key=odd_num.get) 
			odd_change = n/2 - odd_num[odd_max_key]

ans = int(even_change + odd_change)
print(ans)