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>

int main(){
	int n;
	scanf("%d",&n);
	int i,tmp0,tmp1,tmp2,tmp3,ans0=0,ans1=0,f=0;
	for(i=0;i<n;i++){
		if(i==0)scanf("%d",&tmp2);
		else if(i==1)scanf("%d",&tmp3);
		else if(i%2==0){
			scanf("%d",&tmp0);
			if(tmp0!=tmp2)ans0++;
			tmp2=tmp0;
		}else if(i%2==1){
			scanf("%d",&tmp1);
			if(tmp1!=tmp3)ans1++;
			tmp3=tmp1;
		}
		if(i==1&&tmp2==tmp3)f=1;
	}
	if(n/2<ans0)ans0=n/2-ans0;
	if(n/2<ans1)ans1=n/2-ans0;
	printf("%d\n",ans0+ans1+f*n/2);
	return 0;
}