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)

n=gets.to_i
v=gets.split.map(&:to_i)
he,ho={},{}
n.times do |i|
  if i.even?
    if !he.has_key?(v[i])
      he[v[i]]=1
    else
      he[v[i]]+=1
    end
  else
    if !ho.has_key?(v[i])
      ho[v[i]]=1
    else
      ho[v[i]]+=1
    end
  end
end
hemk, hemv = he.max{|x,y| x[1] <=> y[1]}
homk, homv = ho.max{|x,y| x[1] <=> y[1]}
if hemk == homk
  he.delete(hemk)
  ho.delete(homk)
  if he=={}
    hhemv=0
  else
    hhemk, hhemv = he.max{|x,y| x[1] <=> y[1]}
  end
  if ho=={}
    hhomv=0
  else
    hhomk, hhomv = ho.max{|x,y| x[1] <=> y[1]}
  end
  puts n-[hemv+hhomv,homv+hhemv].max
else
  puts n-hemv-homv
end