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: Runtime Error)

#include <iostream>
#include <stdio.h>
#include <string>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <math.h>
#include <vector>
#include <algorithm>
#include <queue>
#include <stack>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;

#define mod ((ull)1e9+7)
//#define MAX ((ull)1e9)
#define MAX ((int)10000)

int main(){
	int oc_max=0, ec_max=0;
	int oc[MAX+1], ec[MAX+1];
	for(int i=0; i<MAX+1; i++){
		oc[i]=0; ec[i]=0;
	}

	int n;
	cin >> n;
	int m=n/2;
	for(int i=0; i<m; i++){
		int v1;
		cin >> v1;
		oc[v1]++;
		if(oc[oc_max]<oc[v1]) oc_max=v1;

		int v2;
		cin >> v2;
		ec[v2]++;
		if(ec[ec_max]<ec[v2]) ec_max=v2;
	}

	int ans=(m-oc[oc_max])+(m-ec[ec_max]);
	if(oc_max==ec_max) ans+=min(oc[oc_max], ec[ec_max]);
	cout << ans << endl;
	return 0;
}