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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
#define ll long long int
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll n,i,temp,ans,n1,n2;
    cin>>n;
    vector<ll> v(n);
    for(i=0;i<n;i++)
    {
        cin>>v[i];
    }
    n1=0;n2=0;
    for(i=0;i<n;i++)
    {
        if(i%2==0)
        {
            if(v[i]!=v[0])
            {
                n1++;
            }
        }
        else
        {
            if(v[i]!=v[1])
            {
                n2++;
            }
        }
    }

    if(v[0]==v[1])
    {
        cout<<(min(n1,n2)+n/2)<<endl;
    }
    else
    {
        cout<<n1+n2<<endl;
    }


}