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: Time Limit Exceeded)

n=gets.to_i
v=gets.split.map &:to_i
a=Array.new(n/2)
b=Array.new(n/2)
(n/2).times{|i|
  a[i]=v[2*i]
  b[i]=v[2*i+1]
}
tr1=a.max_by{|x|a.count(x)}
tr2=b.max_by{|x|b.count(x)}
if tr1>tr2 then
  c=b.count(tr1)
  b.map!{|x|(x==tr1)? 0:x}
  t=b.delete_if{|x|x==0}.map{|x|b.count(x)}.max
  p n-a.count(tr1)-(t ? t:0)
else
  c=a.count(tr2)
  a.map!{|x|(x==tr2)? 0:x}
  t=a.delete_if{|x|x==0}.map{|x|a.count(x)}.max
  p n-b.count(tr2)-(t ? t:0)
end