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
  a:array[1..100000]of longint;
  b:array[1..2,1..100000]of longint;
  n,m,k,i,p,q,o,f,t:longint;
begin
  readln(n);
  for i:=1 to n do 
  begin
     read(a[i]);
	 inc(b[((i-1)mod 2)+1,a[i]]);
	 if a[i]>k then k:=a[i];
  end;
  for i:=1 to k do
  begin
     if b[1,i]>p then begin p:=b[1,i]; o:=i; end;
     if b[2,i]>q then begin q:=b[2,i]; m:=i; end;
  end;
  if o=m then 
  begin 
    if p>q then
	begin
    for i:=1 to k do
	begin
       if (i<>o)and(b[2,i]>=f) then f:=b[2,i];
    end;
	f:=f+p;
	end else
    if p<q then
	begin
    for i:=1 to k do
	begin
       if (i<>o)and(b[1,i]>=f) then f:=b[1,i];
    end;
	f:=f+q;
	end else
	begin
    for i:=1 to k do
	begin
       if (i<>o)and(b[1,i]>=f) then f:=b[1,i];
       if (i<>o)and(b[2,i]>=t) then t:=b[2,i];
    end;
	if t>f then f:=t+p
	else f:=f+p;
	end;
  end else f:=p+q;
  writeln(n-f);
end.