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,a1,a2:array[0..200000] of longint;
  b,c,i,j,k,t,n,m,x,y,xx,yy,x1,y1:longint;
function max(xxx,yyy:longint):longint;
begin
  if xxx>yyy then max:=xxx else max:=yyy;
end;
begin
  readln(n);
  for i:=1 to n do
  begin
    read(a[i]);
    if i mod 2=1 then inc(a1[a[i]]);
    if i mod 2=0 then inc(a2[a[i]]);
  end;
  x:=0; y:=0;
  xx:=0; yy:=0;
  b:=0; c:=0;
  t:=0;
  for i:=1 to 100000 do
  begin
    if a1[i]>b then begin x:=i; b:=a1[i]; end;
    if a2[i]>c then begin y:=i; c:=a2[i]; end;
  end;
  x1:=a1[x]; y1:=a2[y];
  a1[x]:=0; b:=0;
  a2[y]:=0; c:=0;
  for i:=1 to 100000 do
  begin
    if a1[i]>b then begin xx:=i; b:=a1[i]; end;
    if a2[i]>c then begin yy:=i; c:=a2[i]; end;
  end;
  if x=y then t:=max(x1+a2[yy],a1[xx]+y1) else t:=x1+y1;
  writeln(n-t);
end.