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 <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)   FOR(i,0,n)
#define ALL(obj)   (obj).begin(),(obj).end()

#define debug(var)  do{std::cout << __LINE__ << "> " << #var << ": ";view(var);}while(0)
template<typename T> void view(T e){std::cout << e << std::endl;}
template<typename T> void view(const std::vector<T>& v){for(const auto& e : v){ std::cout << e << " "; } std::cout << std::endl;}
template<typename T> void view(const std::vector<std::vector<T> >& vv){ for(const auto& v : vv){ view(v); } }

using namespace std;
using ll = long long;
using vi = vector<int>;
using vl = vector<ll>;
using vvi = vector<vector<int>>;
using vvl = vector<vector<ll>>;

void Main() {
	int n; cin >> n;
	map<int, int> mp1;
	map<int, int> mp2;
	REP(i,n) {
		int v; cin >> v;
		if (i % 2 == 0) mp1[v] += 1;
		else mp2[v] += 1;
	}
	priority_queue<pair<int, int>> pq1;
	priority_queue<pair<int, int>> pq2;
	for (auto p : mp1) {
		pq1.push(make_pair(p.second, p.first));
	}
	for (auto p : mp2) {
		pq2.push(make_pair(p.second, p.first));
	}
	auto _max1 = pq1.top(); pq1.pop();
	auto _max2 = pq2.top(); pq2.pop();
	int _max1_2 = pq1.size() == 0 ? 0 : pq1.top().first;
	int _max2_2 = pq2.size() == 0 ? 0 : pq2.top().first;
	if (_max1.second == _max2.second) {
		int tmp = n - _max1.first - _max2_2;
		tmp = min(tmp, n - _max1_2 - _max2.first);
		cout << tmp << endl;
	} else {
		cout << n - _max1.first - _max2.first << endl;
	}
}

int main() {
    cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	cout << fixed << setprecision(15);
	Main();
}