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())
v=list(map(int,input().split()))
#偶数
eve = [0 for i in range(100000+1)]
#奇数
odd = [0 for i in range(100000+1)]

for i in range(0,n,2):
    eve[v[i]] += 1
for i in range(1,n,2):
    odd[v[i]] += 1

eve_1st_ind = eve.index(max(eve))
odd_1st_ind = odd.index(max(odd))
eve_1st_cnt = max(eve)
odd_1st_cnt = max(odd)

#2番目
eve[eve_1st_ind] = 0
odd[odd_1st_ind] = 0
eve_2nd_ind = eve.index(max(eve))
odd_2nd_ind = odd.index(max(odd))
eve_2nd_cnt = max(eve)
odd_2nd_cnt = max(odd)

#全部同じ文字
if len(set(v))==1: 
    out = n//2
#最初からできてる
elif len(set(eve))==1 and len(set(odd))==1 and (eve_1st_ind!=odd_1st_ind):
    out = 0
elif len(set(eve)) == 1:
    out = n//2- odd_1st_cnt
elif len(set(odd)) == 1:
    out = n//2- eve_1st_cnt
else:
    out1 = n//2-eve_1st_cnt + n//2-odd_2nd_cnt
    out2 = n//2-odd_1st_cnt + n//2-eve_2nd_cnt 
    out = min(out1,out2)
print(out)