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 PyPy3 (2.4.0) (judge verdict: Accepted)

from collections import Counter
n = int(input())
lst = list(map(int, input().split()))

if len(set(lst)) == 1:
    print(n//2)
else:
    a = lst[0:n:2]
    b = lst[1:n:2]

    acnt = Counter(a)
    bcnt = Counter(b)

    amax = acnt.most_common()[0]
    bmax = bcnt.most_common()[0]
    if amax[0] != bmax[0]:
        print((n//2 - amax[1]) + (n//2 - bmax[1]))
    else:
        try:
            asecond = acnt.most_common()[1]
        except:
            asecond = (-1, 0)
        try:
            bsecond = bcnt.most_common()[1]
        except:
            bsecond = (-1, 0)
        res1 = (n//2 - amax[1]) + (n//2 - bsecond[1])
        res2 = (n//2 - asecond[1]) + (n//2 - bmax[1])
        print(min([res1, res2]))