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_array = gets.chomp.split(" ").map(&:to_i)

v_sliced = v_array.each_slice(2)
v_odd = v_sliced.map(&:first)
v_even = v_sliced.map(&:last)

v_odd_g = v_odd.group_by { |e| e }.sort { |e| e[1].length }.reverse
v_even_g = v_even.group_by { |e| e }.sort { |e| e[1].length }.reverse

if v_odd_g[0][0] != v_even_g[0][0]
    puts n - v_odd_g[0][1].length - v_even_g[0][1].length
else
    r1 = v_odd_g[0][1].length + (v_even_g[1] ? v_even_g[1][1].length : 0)
    r2 = (v_odd_g[1] ? v_odd_g[1][1].length : 0) + v_even_g[0][1].length
    puts n - [r1, r2].max
end