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)

l1=[]
l2=[]
n=int(input())
l0=list(map(int,input().split()))
n=0
for x in l0:
  if n%2==0:
    l1.append(x)
  else:
    l2.append(x)
  n+=1
l1.sort()
l2.sort()
setl1=list(set(l1))
setl2=list(set(l2))
a=setl1[0]
b=setl2[0]
a_c=0
a_c_max=[0,0]
maxa=maxb=0
b=setl2[0]
b_c=0
b_c_max=[0,0]
for x in l1:
  if a!=x:
    if a_c_max[0]<a_c:
      a_c_max[1]=a_c_max[0]
      a_c_max[0]=a_c
      maxa=a
    a=x
    a_c=0
  else:
    a_c+=1
if a_c_max[0]<a_c:
  a_c_max[1]=a_c_max[0]
  a_c_max[0]=a_c
  maxa=a
for x in l2:
  if b!=x:
    if b_c_max[0]<b_c:
      b_c_max[1]=b_c_max[0]
      b_c_max[0]=b_c
      maxb=b
    b=x
    b_c=0
  else:
    b_c+=1
if b_c_max[0]<b_c:
  b_c_max[1]=b_c_max[0]
  b_c_max[0]=b_c
  maxb=b
if a!=b:
  print(n-(a_c_max[0]+b_c_max[0]))
else:
  print(min(n-(a_c_max[0]+b_c_max[1]),
    n-(a_c_max[1]+b_c_max[0])))