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 max(int a,int b){

  if(a>=b){
    return a;
  }else{
    return b;
  }

}

int main(){
  int n;
  int v[120000];
  int i;
  int x=0,y=0;
  int countx[120000]={};
  int county[120000]={};
  int tmp;
  int ansx=0;
  int ansy=0;
  int ans;

  scanf("%d",&n);
  for(i=0;i<n;i++){
    scanf("%d",&v[i]);
  }

  for(i=0;i<n;i+=2){
    tmp=v[i];
    countx[tmp]++;
  }

  for(i=1;i<n;i+=2){
    tmp=v[i];
    county[tmp]++;
  }

  for(i=0;i<n;i++){
  x =  max(x,countx[i]);
  }
  for(i=1;i<n;i++){
  y =  max(y,county[i]);
}


  ansx=(n/2)-x;
  ansy=(n/2)-y;
  ans=ansx+ansy;
  if(ans==n&&v[0]!=v[1]){
    ans=0;
  }else if(ans==n&&v[0]==v[1]){
    ans=n/2;
  }
  printf("%d",ans);


  return 0;
  }