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: Wrong Answer)

#include<stdio.h>
#define SIZE 100000

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

int max2(int* cnt, int* list) {
	int i, n, N;
	list[0] = -1; list[1] = -1;
	for (i = 0; i < SIZE; i++) {
		n = cnt[i];
		if (n > list[1]) {
			if (n > list[0]) {
				list[0] = n;
				N = i + 1;
			}
			else {
				list[1] = n;
			}
		}
	}
	return N;
}

int main() {
	int i, n, v[SIZE], e[SIZE], o[SIZE], max_e[2], max_o[2], E, O;
	scanf("%d", &n);
	for (i = 0; i < n; i++) scanf("%d", &v[i]);
	for (i = 0; i < SIZE; i++) e[i] = o[i] = 0;
	for (i = 0; i < n; i += 2) {
		e[v[i] - 1]++; o[v[i + 1] - 1]++;
	}
	printf("%d", n - ((max2(e, max_e) != max2(o, max_o)) ? max_e[0] + max_o[0] : max(max_e[0] + max_o[1], max_e[1] + max_o[0])));
}