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: Accepted)

def get_first(even,even_max_ind,even_second_ind):
    even_max=0
    second=0
    for i in range(1,10**5+1):
        if(even[i]==0):
            continue
        if(even_max<even[i]):
            even_second_ind[0]=even_max_ind.pop()
            second=even[even_second_ind[0]]
            even_max_ind.clear()
            even_max_ind.append(i)
            even_max=even[i]
        elif(even_max==even[i]):
            even_max_ind.append(i)
        elif(second < even[i]):
            even_second_ind[0]=i
            second=even[even_second_ind[0]]


n=int(input())
e_max=0
o_max=0
even=[0]*(10**5+1)
odd=[0]*(10**5+1)
retu=list(map(int,input().split()))
for i in range(n):
    if(i%2==0):
        even[retu[i]]+=1
    else:
        odd[retu[i]]+=1

even_max_ind=[0]
even_second_ind=[0]
odd_max_ind=[0]
odd_second_ind=[0]

get_first(even,even_max_ind,even_second_ind)
get_first(odd,odd_max_ind,odd_second_ind)

if(len(even_max_ind)>=2 or len(odd_max_ind)>=2 or even_max_ind[0]!=odd_max_ind[0]):
    print(n-even[even_max_ind[0]] - odd[odd_max_ind[0]])
else:
    print(n-max([even[even_second_ind[0]] + odd[odd_max_ind[0]],even[even_max_ind[0]] + odd[odd_second_ind[0]]]))