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 (3.8.2) (judge verdict: Accepted)

from collections import Counter
import sys
n = int(input())
v = [[], []]
for i, j in enumerate(input().split()):
    if i & 1:
        v[0].append(int(j))
    else:
        v[1].append(int(j))

v1, v2 = Counter(v[0]), Counter(v[1])
mx1 , mx2 = v1.most_common()[0], v2.most_common()[0]
if mx1[0] == mx2[0]:
    if mx1[1] + mx2[1] == n:
        print(n//2)
        sys.exit() 
    nx1, nx2 = v1.most_common()[1][1], v2.most_common()[1][1]# 次に最も多い数
    if nx1 > nx2:
        print(n - nx1 - mx2[1])
    else:
        print(n - mx1[1] - nx2)
else:
    print(n - mx1[1] - mx2[1])