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)

import collections
n=int(input())
V=list(map(int,input().split()))
VO=[]
VE=[]
for i in range(n):
  if i%2==0:
    VO.append(V[i])
  else:
    VE.append(V[i])
vo=collections.Counter(VO).most_common()
ve=collections.Counter(VE).most_common()
if ve[0][0]!=vo[0][0]:
  ans=n-ve[0][1]-vo[0][1]
else:
  if len(ve)==1 and len(vo)==1:
    ans=min(ve[0][1],vo[0][1])
  elif len(ve)==1 and len(vo)!=1:
    ans=len(VO)-vo[1][1]
  elif len(ve)!=1 and len(vo)==1:
    ans=len(VE)-ve[1][1]
  elif len(ve)!=1 and len(vo)!=1:
    ans=min((n-ve[0][1]-vo[1][1]),(n-vo[0][1]-ve[0][1]))    
print(ans)