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 = list(map(int, input().split()))

v0 = [v[i] for i in range(0,n,2)]
v1 = [v[i] for i in range(1,n,2)]

v0cnt = collections.Counter(v0)
v1cnt = collections.Counter(v1)

v0most = v0cnt.most_common()[0]
v1most = v1cnt.most_common()[0]
if v0most[0] != v1most[0]:
    ans = n - v0most[1] -v1most[1]
else:
    if v0most[1] == v1most[1]:
        if v0most[1] == n//2:
            ans = n//2
        else:
            if v0cnt.most_common()[1] > v1cnt.most_common()[1]:
                ans = n - v0most[1] - v0cnt.most_common()[1][1]
            else:
                ans = n - v0most[1] - v1cnt.most_common()[1][1]            
    elif v0most[1] > v1most[1]:
        ans = n - v0most[1] - v1cnt.most_common()[1][1]
    else:
        ans = n - v1most[1] - v0cnt.most_common()[1][1]

print(ans)