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 (GCC 5.4.1) (judge verdict: Accepted)

/* Coached by rainboy */
#include <stdio.h>
#include <string.h>

#define N 100000
#define V 100000

int max(int a, int b) {
	return a > b ? a : b;
}

int main() {
	static int vv[N], kk[V + 1], mm1[2], mm2[2];
	int n, i, max1, max2, v_, v, r;

	scanf("%d", &n);
	for (i = 0; i < n; i++)
		scanf("%d", &vv[i]);
	for (r = 0; r < 2; r++) {
		memset(kk, 0, sizeof kk);
		for (i = r; i < n; i += 2)
			kk[vv[i]]++;
		max1 = max2 = 0;
		v_ = -1;
		for (v = 0; v <= V; v++)
			if (max1 < kk[v]) {
				max2 = max1;
				max1 = kk[v];
				v_ = v;
			} else if (max2 < kk[v])
				max2 = kk[v];
		mm1[r] = max1;
		mm2[r] = max2;
		vv[r] = v_;
	}
	printf("%d\n", n - (vv[0] != vv[1] ? mm1[0] + mm1[1] : max(mm1[0] + mm2[1], mm1[1] + mm2[0])));
	return 0;
}