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: Wrong Answer)

import math
N=int(input())
V=list(map(int,input().split()))
counter = [dict() for _ in range(2)]
for i in range(N):
  if V[i] in counter[i%2]:
    counter[i%2][V[i]] += 1
  else:
    counter[i%2][V[i]] = 1
max_v = [[0,0],[0,0]]
max_k = [[-1,-1],[-1,-1]]
for i in range(2):
  for k,v in counter[i].items():
    if max_v[i][0] < v:
      max_v[i] = [v, max_v[i][0]]
      max_k[i] = k
    elif max_v[i][1] < v:
      max_v[i][1] = v
if max_k[0] != max_k[1]:
  print(N-max_v[0][0]-max_v[1][0])
elif N%2 or max_v[0][0] > max_v[1][0]:  # おなじでも奇数なら奇数回めの方をかえる
  print(N-max_v[0][0]-max_v[1][1])
else:
  print(N-max_v[0][1]-max_v[1][0])