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 = gets.to_i
v = gets.split(" ").map(&:to_i)

if v.uniq.length == 1
    puts n / 2
    exit
end

v_even = Array.new
v_odd = Array.new


for i in 0 .. n-1 do
    if i % 2 == 0
        v_even << v[i]
    else
        v_odd << v[i]
    end
end

count_even = Hash.new(0)
count_odd = Hash.new(0)

v_even.each do |elem|
    count_even[elem] += 1
end

v_odd.each do |elem|
    count_odd[elem] += 1
end

# 　偶数番目奇数番目それぞれで一番あらわれる数の個数の合計
sum = count_even.max_by{|j,k| k }[1] + count_odd.max_by{|j,k| k }[1]

puts n - sum