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)

import collections

n = int(input())
v = [int(i) for i in input().split()]
odd = collections.Counter(v[1::2])
even = collections.Counter(v[0::2])
# print(odd)

max_odd = max(odd, key=odd.get)
# print(max_odd)
max_even = max(even, key=even.get)
# print(max_even)

max_odd_v = odd[max_odd]
max_even_v = even[max_even]
if max_odd == max_even:
    if max_odd_v < max_even_v:
        del(odd[max_odd])
        if len(odd) > 0:
            max_odd = max(odd, key=odd.get)
            max_odd_v = odd[max_odd]
        else:
            max_odd_v = 0
    else:
        del(even[max_even])
        if len(even) > 0:
            max_even = max(even, key=even.get)
            max_even_v = even[max_even]
        else:
            max_even_v = 0

num_change_odd = int(n / 2) - max_odd_v
num_change_even = int(n / 2) - max_even_v
print(num_change_odd + num_change_even)