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(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n,a,b,emax,omax,em,om;
  emax=0;omax=0;
  vector<int> ec(100001,0);
  vector<int> oc(100001,0);
  cin>>n;
  for(int i=0;i<n/2;i++){
    cin>>a>>b;
    ec[a]++;oc[b]++;
    if(ec[a]>emax){emax=ec[a];em=a;}
    if(oc[b]>omax){omax=oc[b];om=b;}
  }
  sort(ec.rbegin(),ec.rend());
  sort(oc.rbegin(),oc.rend());
  if(em!=om){cout<<n-oc[0]-ec[0];}
  else{cout<<min(n-oc[1]-ec[0],n-ec[1]-oc[0]);}
}