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 <iostream>
#include <cstdio>
using namespace std;
int n, mx[2], mi[2], my[2], ans, a[2][100005];
int main() {
	int i, j, t;
	cin>>n;
	for(i=0; i<n; i++) scanf("%d", &t), a[i%2][t]++;
	for(i=0; i<2; i++) for(j=1; j<=100000; j++) {
		if(a[i][j] > mx[i]) mx[i] = a[i][j], mi[i] = j;
	}
	if(mi[0] != mi[1]) ans = n - mx[0] - mx[1];
	else {
		for(i=0; i<2; i++) for(j=1; j<=100000; j++) {
			if(j == mi[0]) continue;
			if(a[i][j] > my[i]) my[i] = a[i][j];
		}
		ans = n - max(mx[0] + my[1], mx[1] + my[0]);
	}
	cout<<ans;
	return 0;
}