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 Ruby (2.3.3) (judge verdict: Wrong Answer)

n = gets.to_i
raw_array = gets.chomp.split(' ').map(&:to_i)
count = 0

even_array = []
odd_array = []

raw_array.each_with_index do |item, idx|
  if idx % 2 == 0
    even_array << item
  else
    odd_array << item
  end
end

even_count_array = []
even_array.uniq.map {|e|
  even_count_array << even_array.count(e)
}

odd_count_array = []
odd_array.uniq.map {|e|
  odd_count_array << odd_array.count(e)
}


even_count_min = even_count_array.min
odd_count_min = odd_count_array.min

if even_count_array.length == 1
  even_count_min = 0
end

if odd_count_array.length == 1
  odd_count_min = 0
end

if even_array == odd_array
  even_count_min = even_array.length
  odd_count_min = 0
end

puts even_count_min + odd_count_min