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 <iostream>
#include <iomanip>
#include <bits/stdc++.h>
#include <vector>
#include <iterator>
#include <string>
#define pan(i,n) for(int i=0;i<n;i++)
#define ll long long int
#define vi vector<int>
#define pb push_back
#define INF 1e9+7
#define PI 3.141592653
#define inf 200001
using namespace std; 


int main(){
    int n;
    cin>>n;
    vi v,p;
    pan(i,n){int x;
        cin>>x;
        if(i%2==0) v.pb(x);
        else p.pb(x);
    }
    int o=0,o1=-1,e=0,e1=-1,x[inf],y[inf];
    memset(x,0,sizeof(x));
    memset(y,0,sizeof(y));
    for(int i=0;i<v.size();i++) x[v[i]]++;
    int ce=*max_element(x,x+inf);
    e=distance(x,max_element(x,x+inf));
    x[e]=0;
    int ce1=*max_element(x,x+inf);
    e1=distance(x,max_element(x,x+inf));
    pan(i,p.size()) y[p[i]]++;
    int co=*max_element(y,y+inf);
    o=distance(y,max_element(y,y+inf));
    y[o]=0;
    int co1=*max_element(y,y+inf);
    o1=distance(y,max_element(y,y+inf));
    int ans=0;
    if(o!=e) ans=n-co-ce;
    else{
        ans=min(n-co-ce1,n-co1-ce);
    }
    // cout<<co<<" "<<ce1<<endl;
    cout<<ans;
}