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: Accepted)

class Array
  def even; select.with_index{|_,i| i.even? } end
  def odd; select.with_index{|_,i| i.odd? } end
  def counter; h = Hash.new(0); each{ |t| h[t]+=1 }; h end
end

n = gets.to_s.to_i
v = gets.to_s.split.map{|t| t.to_i }

s =  v.even.counter.sort_by{|_,s|-s}
t =  v.odd.counter.sort_by{|_,s|-s}

if s.first != t.first
  puts n - s[0].last - t[0].last
else
  ans = n - s[0].last
  n1 = n - t[0].last
  n2 = n3 = 10 ** 5 + 1
  t[1] && n2 = n - s[0].last - t[1].last
  s[1] && n3 = n - s[1].last - t[0].last
  
  ans = n1 if ans > n1
  ans = n2 if ans > n2
  ans = n3 if ans > n3
  
  puts ans
end