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,j,k,t,x,p1,p2,q1,q2,maxa1,maxa2,maxb1,maxb2:longint;
  a,b:array[1..100000] of longint;
function max(x,y:longint):longint;
  begin
    if x>y
      then exit(x)
      else exit(y);
  end;
begin
  readln(n);
  for i:=1 to n do
    begin
      read(x);
      if i mod 2=0
        then inc(b[x])
        else inc(a[x]);
    end;
  for i:=1 to 100000 do
    begin
      if a[i]>maxa1
        then
          begin
            maxa2:=maxa1;
            maxa1:=a[i];
            p1:=i;
          end
        else
      if a[i]>maxa2
        then maxa2:=a[i];
    end;
  for i:=1 to 100000 do
    begin
      if b[i]>maxb1
        then
          begin
            maxb2:=maxb1;
            maxb1:=b[i];
            q1:=i;
          end
        else
          if b[i]>maxb2
            then maxb2:=b[i];
    end;
  if p1<>q1
    then writeln(n-maxa1-maxb1)
    else writeln(n-max(maxa1+maxb2,maxa2+maxb1));
end.