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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

var
  n,i,x,maxo,maxj,oi,ji,maxo2,maxj2:longint;
  j,o:array[1..100000]of longint;
begin
  read(n);
  for i:=1 to n do
    begin
	  read(x);
	  if i mod 2=0 then inc(o[x])
	  else inc(j[x]);
	end;
  maxo:=-maxlongint;
  maxj:=-maxlongint;
  for i:=1 to 100000 do
    begin
    if o[i]>maxo then begin maxo:=o[i]; oi:=i; end;
	if j[i]>maxj then begin maxj:=j[i]; ji:=i; end;
	end;
  if oi=ji then begin
    o[oi]:=-maxlongint;
	j[ji]:=-maxlongint;
  maxo2:=-maxlongint;
  maxj2:=-maxlongint;
  for i:=1 to 100000 do
    begin
    if o[i]>maxo2 then begin maxo2:=o[i]; oi:=i; end;
	if j[i]>maxj2 then begin maxj2:=j[i]; ji:=i; end;
	end;
  if maxo2>=maxj2 then write(n-maxo2-maxj)
  else write(n-maxj2-maxo);
  end
  else write(n-maxo-maxj);
end.