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.chomp.split(' ').map{|n| n.to_i}
icnt = 0
hevn = {}
hodd = {}
gets.chomp.split(' ').map{|n| n.to_i}.each{|i|
	case icnt%2
	when 0
		hevn[i].nil? ? hevn[i] = 1 : hevn[i]+=1
	when 1
		hodd[i].nil? ? hodd[i] = 1 : hodd[i]+=1
	end
	icnt+=1
}
evnsorted = hevn.sort{|a,b| b[1] <=> a[1]}
oddsorted = hodd.sort{|a,b| b[1] <=> a[1]}
# p evnsorted
# p oddsorted
evnmax = evnsorted[0]
oddmax = oddsorted[0]
evnmaxnum = evnmax[1]
oddmaxnum = oddmax[1]
evnmax2num = !evnsorted[1].nil? ? evnsorted[1][1] : 0 
oddmax2num = !oddsorted[1].nil? ? oddsorted[1][1] : 0
if(evnmax[0] == oddmax[0])
	case evnmax2num <=> oddmax2num
	when 1
		evnmaxnum = evnmax2num
	when -1,0
		oddmaxnum = oddmax2num
	end
end
puts "#{N-evnmaxnum-oddmaxnum}"