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())
v = [int(i) for i in input().split()]
odd = [v[i] for i in range(n) if i % 2 == 1]
even = [v[i] for i in range(n) if i % 2 == 0]
summ_odd = {i: odd.count(i) for i in set(odd)}
summ_even = {i: even.count(i) for i in set(even)}
odd_max_k = max(summ_odd.items(), key=lambda x: x[1])[0]
even_max_k = max(summ_even.items(), key=lambda x: x[1])[0]
if odd_max_k == even_max_k:
    if len(summ_odd) >= 1:
        if len(summ_even) >= 1:
            print(n//2)
            exit()
        else:
            tmp = summ_even.pop(even_max_k)
            even_max_k = max(summ_even.items(), key=lambda x: x[1])[0]
            summ_even.upddate(tmp)
    else:
        tmp = summ_odd.pop(odd_max_k)
        odd_max_k = max(summ_odd.items(), key=lambda x: x[1])[0]
        summ_odd.upddate(tmp)

summ_odd.pop(odd_max_k)
summ_even.pop(even_max_k)
res = sum(summ_odd.values()) + sum(summ_even.values())
print(res)