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)

from sys import stdin

n = int(stdin.readline().rstrip())
v = [int(i) for i in stdin.readline().rstrip().split()]

left = [0] * (10**5 + 1)
right = [0] * (10**5 + 1)

for i in range(len(v)):
    if i % 2 == 0:
        left[v[i]] += 1
    else:
        right[v[i]] += 1

left_max = 0
left_max_second = 0
right_max = 0
right_max_second = 0
left_flag = 0
right_flag = 0
for i in range(len(left)):
    if left_max < left[i]:
        left_max_second = left_max
        left_max = left[i]
        left_flag = i

    if right_max < right[i]:
        right_max_second = right_max
        right_max = right[i]
        right_flag = i

if left_flag == right_flag:
    tmp = max(left_max + right_max_second, right_max + left_max_second)
    # print(left_max, left_max_second, right_max, right_max_second)
    print(n - tmp)
else:
    print((n // 2 - left_max) + (n // 2 - right_max))