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 C (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>
     
int main(){
   int n,i,j,gun[100001],kin[100001],mg,mgi,mg2,mgi2,mk,mki,mk2,mki2;
    
   scanf("%d",&n);
   for (i=0;i<=100000;i++) gun[i]=kin[i]=0;
   for (i=0;i<n;i++) {
     scanf("%d",&j);
     if (i%2==0) gun[j]++;
     else        kin[j]++;
   }

   mg=mg2=-1;
   for (i=1;i<=100000;i++)
      if (mg<gun[i]) {
         mg2=mg;mgi2=mgi;mg=gun[i];mgi=i;
      } else if (mg2<gun[i]) {
         mg2=gun[i];mgi2=i;
      }

   mk=mk2=-1;
   for (i=1;i<=100000;i++)
      if (mk<kin[i]) {
         mk2=mk;mki2=mki;mk=kin[i];mki=i;
      } else if (mk2<kin[i]) {
         mk2=kin[i];mki2=i;
      }

   if (mki!=mgi) printf("%d\n",n-mk-mg);
   else if (mk+mg2>mk2+mg) printf("%d\n",n-mk-mg2);
   else printf("%d\n",n-mk2-mg);
   return 0;
}