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)

# sys.stdin.readline()
import sys
input = sys.stdin.readline
from collections import Counter

n = int(input())
v = list(map(int, input().split()))
w = [0]*(n//2)
x_c = Counter(v)

if x_c.most_common()[0][1] == n:
    ans = n//2
else:
    for i in range(n//2):
        w[i] = v.pop(2*i - i)
    v_0 = Counter(v).most_common()[0][1]
    w_0 = Counter(w).most_common()[0][1]
    if x_c.most_common()[0][1]*2 > n:
        if len(Counter(v)) == 1:
            ans = n//2 - Counter(w).most_common()[1][1]
        elif len(Counter(w)) == 1:
            ans = n//2 - Counter(v).most_common()[1][1]
        else:
            if v_0 > w_0:
                ans = n - (Counter(w).most_common()[1][1] + v_0)
            else:
                ans = n - (Counter(v).most_common()[1][1] + w_0)
    else:
        ans = n - (w_0 + v_0)
print(ans)