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,L,R,x,y,z,w:Longint;
	a,b:Array[0..100000]of Longint;
begin
	read(N);
	for i:=1 to N do begin
		read(x);
		if i mod 2=1 then inc(a[x])else inc(b[x]);
	end;
	x:=0;
	for i:=1 to 100000 do begin
		if a[x]<a[i]then begin
			y:=x;
			x:=i;
		end else if a[y]<a[i]then begin
			y:=i;
		end;
		if b[z]<b[i]then begin
			w:=z;
			z:=i;
		end else if b[w]<b[i]then begin
			w:=i;
		end;
	end;
	if x<>z then writeln(N-a[x]-b[z])else begin
		L:=N-a[y]-b[z];
		R:=N-a[x]-b[w];
		if L<R then writeln(L)else writeln(R);
	end;
end.