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: Time Limit Exceeded)

from collections import Counter
n=int(input())
l=list(map(int,input().split()))
f=l[0::2]
s=l[1::2]
ans=[]
if len(Counter(l).values()) == 1:
  ans.append(len(f))
elif len(Counter(f).values()) == len(Counter(s).values()) == 1:
  ans.append(0)
else:
  for fk,fv in Counter(f).items():
    fdk=fk
    a=sum(Counter(f).values())-fv
    for sk,sv in Counter(s).items():
      if fk != sk:
        ans.append(a+sum(Counter(s).values())-sv)
print(min(ans))