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
  maxn1,maxn2,who1,who2,maxn3,maxn4:longint;
  i,j,m,n,k,p,len1,len2:longint;
  check1,check2:array[0..100005]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(k);
      if i mod 2=1 then inc(check1[k])
      else inc(check2[k]);
    end;
  for i:=1 to 100000 do
    if check1[i]>maxn1 then
      begin
        maxn1:=check1[i]; who1:=i;
      end;

  for i:=1 to 100000 do
    if (i<>who1)and(check1[i]>maxn3) then
      maxn3:=check1[i];

  for i:=1 to 100000 do
    if check2[i]>maxn2 then
      begin
        maxn2:=check2[i]; who2:=i;
      end;

  for i:=1 to 100000 do
    if (i<>who2)and(check2[i]>maxn4) then
      maxn4:=check2[i];

  if who1<>who2 then
    writeln(n-maxn1-maxn2)
  else           
    writeln(n-max(maxn1+maxn4,maxn2+maxn3));
end.