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: Accepted)

from collections import Counter
n = int(input())
v = list(map(int, input().split()))
gu = v[::2]
ki = v[1::2]
ans = 0
k,g = False,False

if v.count(v[0]) == n:#全部同じ
    ans += n // 2
else:
    kic = Counter(ki)
    guc = Counter(gu)
    k1 = kic.most_common(2)
    g1 = guc.most_common(2)
    if k1[0][0] == g1[0][0]:
        if k1[1][1] < g1[1][1]:
            k = True
        else:
            g = True

    kic = list(kic.values())
    guc = list(guc.values())
    kic.sort(reverse = True)
    guc.sort(reverse = True)
    if len(kic) != 1:
        if g:
            ans += kic[0]
            ans += sum(kic[2::])
        else:
            ans += sum(kic[1::]) 
    if len(guc) != 1:
        if k:
            ans += guc[0]
            ans += sum(guc[2::])
        else:
            ans += sum(guc[1::])

print(ans)