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=readline.to_i
vs = readline.chomp.split.map(&:to_i)

evens = []
odds = []
(N/2).times do |i|
  evens << vs[i*2]
  odds << vs[i*2+1]
end

e_count = {}
o_count = {}
evens.each {|v| e_count[v] = e_count[v].to_i + 1 }
odds.each {|v| o_count[v] = o_count[v].to_i + 1 }
e_count = e_count.sort_by {|k,v| v }.reverse
o_count = o_count.sort_by {|k,v| v }.reverse

#pp e_count, o_count
if e_count[0][0] != o_count[0][0]
  puts N - (e_count[0][1] + o_count[0][1])
else
  e_count.each_with_index do |ev,i|
    ov = o_count[i]
    if ev[1] > ov[1]
      puts N/2-(ev[1]) + N/2-(o_count[0][1])
      break
    elsif ev[1] < ov[1]
      puts N/2-(ov[1]) + N/2-(e_count[0][1])
      break
    end
  end
  if e_count.size > 1
    puts N/2-(e_count[1][1]) + N/2-(o_count[0][1])
  else
    puts N/2 + N/2-(o_count[0][1])
  end
end