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 Python (3.4.3) (judge verdict: Wrong Answer)

N = int(input())
A = input().split(" ")
A = [int(i) for i in A]

def mostFrequent(arr, n): 
    arr.sort() 
    max_count = 1; res = arr[0]; curr_count = 1
    for i in range(1, n):  
        if (arr[i] == arr[i - 1]): 
            curr_count += 1
        else : 
            if (curr_count > max_count):  
                max_count = curr_count 
                res = arr[i - 1] 
            curr_count = 1
    if (curr_count > max_count): 
        max_count = curr_count 
        res = arr[n - 1] 
    return max_count 

# print(A[::2])
ans = 0
if len(A) >2 :
	if len(set(A[::2])) != 1:
		# print("1")
		k = mostFrequent(A[::2],len(A[::2]))
		ans += len(A[::2])-k 
	if len(set(A[1::2])) != 1:
		k = mostFrequent(A[1::2],len(A[1::2]))
		ans += len(A[1::2])-k
else:
	if A[0] == A[1]:
		ans +=1
print(ans)