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,x,i,max,min,atot1,atot2,btot1,btot2,ta,tb:longint;
    a,b:array[0..100010] of longint;
begin
    readln(n);
    max:=0;min:=maxlongint;
    fillchar(a,sizeof(a),0);
    fillchar(b,sizeof(b),0);
    for i:=1 to n do
        begin
            read(x);
            if odd(i) then inc(a[x]) else inc(b[x]);
            if x>max then max:=x 
            else if x<min then min:=x;
        end;
    for i:=min to max do
        begin
            if a[i]>atot1 then 
                begin 
                    atot2:=atot1;atot1:=a[i];ta:=i;
                end
            else if a[i]>=atot2 then atot2:=a[i];
            if b[i]>btot1 then
                begin 
                    btot2:=btot1;btot1:=b[i];tb:=i;
                end
            else if b[i]>=btot2 then btot2:=b[i];
        end;
    if ta<>tb then writeln(n-atot1-btot1)
    else if atot1+btot2>atot2+btot1 then writeln(n-atot1-btot2)
    else writeln(n-atot2-btot1);
end.