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,t1,t2:array[0..500005]of longint;
 n,m,i,j,k1,k2,tot1,tot2,j1,j2,p1,p2:longint;
 ans:int64;
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(a[i]);
  if m<a[i] then m:=a[i];
 end;
for i:=1 to n do
 begin
   if i mod 2=0 then begin inc(t1[a[i]]);  end;
   if i mod 2=1 then begin inc(t2[a[i]]);  end;
 end;
  for i:=1 to m do
  begin
    if k1<t1[i] then begin k1:=t1[i];p1:=i; end;
    if k2<t2[i] then begin k2:=t2[i];p2:=i; end;
  end;
  if p1<>p2 then
   begin
     ans:=n-k1-k2;
   end
    else
      begin
      j1:=0;j2:=0;
       for i:=1 to m do
        begin
         if i=p1 then continue;
         if j1<t1[i] then begin j1:=t1[i]; end;
         if j2<t2[i] then begin j2:=t2[i]; end;
        end;
       if j1<j2 then ans:=n-j2-k1 else ans:=n-j1-k2;
      end;
      writeln(ans);
end.