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)

#define _USE_MATH_DEFINES
#include <iostream>
#include <numeric>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <iterator>
#include <math.h>
#include <cmath>
#include <set>   

using namespace std;
long long a[100050];

int main() {
	long long n;
	cin >> n;
	long long cntX = 0;
	long long cntY = 0;
	for (int i = 0; i < n; i++)
	{
		cin >> a[i];
	}

	sort(a, a + n);

	if (a[0] == a[n - 1]) {
		cout << n / 2 << endl;
		return 0;
	}

	long long x = a[0];
	long long y = a[n / 2];

	for (long long i = 0; i < n / 2 ; i++)
	{
		if (x != a[i]) {
			cntX++;
		}
	}

	for (long long i = n / 2; i < n; i++)
	{
		if (y != a[i]) {
			cntY++;
		}
	}

	if (cntX > n / 4) {
		cntX = n / 2 - cntX;
	}

	if (cntY > n / 4) {
		cntY = n / 2 - cntY;
	}

	if (a[0] == a[n / 2])
	{
		cntY = n / 2 - cntY;
	}


	cout << cntX + cntY << endl;
}