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 inf 1<<30
#define llong long long
#define usd unsigned
#define pqueue priority_queue
#define mp make_pair
#define pb push_back
#define fn fill_n
#define P pair<int, int>
struct data{
	int place;
	int cost;

	bool operator<(const data &ri) const{
		return cost < ri.cost;
	}
	bool operator>(const data &ri) const{
		return cost > ri.cost;
	}
};
int nw[9] = {0, 1, 0, -1, -1, 1, 1, -1, 0};
int nh[9] = {1, 0, -1, 0, 1, 1, -1, -1, 0};



int main(){
	int n;
	map<int, int> a,b;
	int in;
	cin >> n;
	for(int i = 0; i < n; i++){
		cin >> in;
		if(i%2)a[in]++;
		else b[in]++;
	}

	int amaxi[2] = {0, 0}, bmaxi[2] = {0, 0};
	set<int> an, bn;
	for(auto it = a.begin(); it != a.end(); it++){
		if(amaxi[0] < it->second){
			amaxi[1] = amaxi[0];
			amaxi[0] = it->second;
			an.clear();
			an.insert(it->first);
		}else if(amaxi[0] == it->second){
			an.insert(it->first);
		}
	}
	for(auto it = b.begin(); it != b.end(); it++){
		if(bmaxi[0] < it->second){
			bmaxi[1] = bmaxi[0];
			bmaxi[0] = it->second;
			bn.clear();
			bn.insert(it->first);
		}else if(bmaxi[0] == it->second){
			bn.insert(it->first);
		}
	}

	// cout << amaxi[0] << amaxi[1] << bmaxi[0] << bmaxi[1] << endl;
	if(an.size() == bn.size() && an.size() == 1 && *an.begin() == *bn.begin()){
		cout << n - max(amaxi[0] + bmaxi[1], amaxi[1] + bmaxi[0]) << endl;
	}else cout << n - amaxi[0] - bmaxi[0] << endl;

	return 0;
}