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 as cl

n=int(input())
vlist=list(map(int,input().split()))

vg=vlist[0::2]
vk=vlist[1::2]

vgcnt=cl.Counter(vg)
vkcnt=cl.Counter(vk)

vgmax=max(vgcnt,key=vgcnt.get)
vkmax=max(vkcnt,key=vkcnt.get)

if vgmax==vkmax:
    if vgcnt[vgmax]<vkcnt[vkmax]:
        vgcnt.pop(vgmax)
        if len(vgcnt)!=0:
            vgmax=max(vgcnt)
        else:
            vgmax+=1
    else:
        vkcnt.pop(vkmax)
        if len(vkcnt)!=0:
            vkmax=max(vkcnt)
        else:
            vkmax+=1

ans=0
for i in range(len(vg)):
    if vg[i]!=vgmax:
        ans+=1
for i in range(len(vk)):
    if vk[i]!=vkmax:
        ans+=1

print(ans)