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
os = {}
es = {}
gets.split.map(&:to_i).each_with_index{ |a,i|
  if i%2 == 0
    es[a] = (es[a] || 0) + 1
  else
    os[a] = (os[a] || 0) + 1
  end
}
ke = es.keys.sort_by{ |a| -es[a] }
ko = os.keys.sort_by{ |a| -os[a] }
if ke[0] == ko[0]
  p N - [((es[ke[1]] || 0) + os[ko[0]]), ((os[ko[1]] || 0) + es[ke[0]])].max
else
  p N - es[ke[0]] - os[ko[0]]
end