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>
#include <stdlib.h>

int main(void) {
	int n;

	scanf("%d", &n);

	int v[n];

	for(int i = 0;i < n;i++) {
		scanf("%d", &v[i]);
	}

	int hoge = v[0];
	int baka = v[1];
	int flag = 0;
	if(hoge == baka) {
		flag = 1;
	}
	int sum = 0;

	for(int i = 0;i < n;i++) {
		if(i % 2 == 0) {
			if(hoge != v[i]) {
				sum += 1;
			}
		} else {
			if(baka != v[i]) {
				sum += 1;
			}
			if(flag == 1) {
				sum += 1;
			}
		}
	}

	printf("%d\n", sum);
}