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 (2.7.1) (judge verdict: Accepted)

n = gets.to_i
ary = gets.strip.split.map(&:to_i)
odd = []
even = []
n.times do |i|
  if i%2==0
    odd << ary[i]
  else
    even << ary[i]
  end
end
rec1 = Array.new(10**5,0)
rec2 = Array.new(10**5,0)
for i in 0..n/2-1
  rec1[odd[i]-1] += 1
end
for i in 0..n/2-1
  rec2[even[i]-1] += 1
end
recs1 = rec1.sort
recs2 = rec2.sort
if rec1.count(recs1[-1])==1 && rec2.count(recs2[-1])==1
  if rec1.index(recs1[-1]) == rec2.index(recs2[-1])
    puts [n-recs1[-2]-recs2[-1],n-recs1[-1]-recs2[-2]].min
  else
    puts n-recs1[-1]-recs2[-1]
  end
else
  puts n-recs1[-1]-recs2[-1]
end