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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
using namespace std;
int main(){
  int n;
  cin >> n;
  int v;
  int Even[100001]={};
  int Odd[100001]={};
  int i;
  int odd1,odd2,even1,even2;
  for(i=0;i<n/2;i++){
    cin >> v;
    Odd[v]++;
    cin >> v;
    Even[v]++;
  }
  odd1 = 0;
  odd2 = 0;
  even1 = 0;
  even2 = 0;
  for(i=1;i<=100000;i++){
    if(Odd[i]>=Odd[odd1]){
      odd2 = odd1;
      odd1 = i;
    }else if(Odd[i]>=Odd[odd2]){
      odd2 = i;
    }
    if(Even[i]>=Even[even1]){
      even2 = even1;
      even1 = i;
    }else if(Even[i]>=Even[even2]){
      even2 = i;
    }
  }
  int ans = 0;
  if(odd1 != even1){
    ans = n-Odd[odd1]-Even[even1];
  }else{
    if(Odd[odd1]-Odd[odd2]<=Even[even1]-Even[even2])ans = n-Odd[odd2]-Even[even1];
    else ans = n-Odd[odd1]-Even[even2];
  }
  cout << ans;

}