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: Wrong Answer)

#include <stdio.h>
int main (){
int n,k[100001],i,a[100000]={0},b[100000]={0},maxa=0,maxb=0,kia,kib;
  scanf ("%d",&n);
  for (i=0;i<n;i++){
    scanf ("%d",&k[i]);
  }
  for (i=0;i<(n/2);i=i+2){
  a[k[i]]++;
  if (maxa<a[k[i]]){
  maxa=a[k[i]];
  kia=k[i];
  }
  }
  for (i=1;i<(n/2)+1;i=i+2){
  b[k[i]]++;
  if (maxa<b[k[i]]){
  maxb=b[k[i]];
  kib=k[i];
  }
  }
  if (kia==kib){
  printf ("%d",n/2);
  }
  else {
  printf ("%d",n-maxa-maxb);
  }
return 0;
}