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: Wrong Answer)

var
a:array[1..100000]of longint;
b:array[0..1,0..100000]of longint;
max:array[0..1]of longint;
n,i,s,t,x:longint;
begin
read(n);
for i:=1 to n do
begin
read(a[i]);
inc(b[i mod 2,a[i]]);
 if b[i mod 2,a[i]]>max[i mod 2] then
 begin
 max[i mod 2]:=b[i mod 2,a[i]];
 b[i mod 2,0]:=a[i];
 end;
end;
if b[0,0]=b[1,0] then
begin
t:=0;
 for i:=1 to n do
  if (i mod 2=0) and (a[i]<>b[0,0]) and (b[0,a[i]]>t) then
  begin
  t:=b[0,a[i]];
  x:=a[i];
  end;
s:=0;
 for i:=1 to n do
  if (i mod 2=0) and (a[i]<>x) or (i mod 2=1) and (a[i]<>b[1,0]) then
  inc(s);
t:=0;
 for i:=1 to n do
  if (i mod 2=1) and (a[i]<>b[1,0]) and (b[1,a[i]]>t) then
  begin
  t:=b[1,a[i]];
  x:=a[i];
  end;
t:=0;
 for i:=1 to n do
  if (i mod 2=0) and (a[i]<>b[0,0]) or (i mod 2=1) and (a[i]<>x) then
  inc(t);
 if t>s then
 writeln(t)
 else
 writeln(s);
halt;
end;
for i:=1 to n do
 if a[i]<>b[i mod 2,0] then
 inc(s);
writeln(s);
end.