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: Runtime Error)

import collections
n = int(input())
v = list(map(int,input().split()))
ans = 0
lia = v[::2]
lib = v[1::2]
tmp1 = len(lia)
tmp2 = len(lib)
lia.sort()
lib.sort()
if lia[0]==lib[-1]:
  print(n//2)
  exit()
lib.sort(reverse=True)
lia = collections.Counter(lia)
lib = collections.Counter(lib)
ans += tmp1-lia.most_common()[0][1]
ans += tmp2-lib.most_common()[0][1]
if lia.most_common()[0][1]%2==1 and lib.most_common()[0][1]2==1:
  print(ans+1)
else:
  print(ans)