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: Accepted)

n = int(input())
u = list(map(int, input().split()))
u0 = u[0::2]
u1 = u[1::2]
s0 = [0] * 100001
s1 = [0] * 100001
for i in u0:
  s0[i] += 1
for i in u1:
  s1[i] += 1
maxi_0 = 0
maxi2_0 = 0
for i in range(100001):
  if s0[i] >= s0[maxi_0]:
    maxi2_0 = maxi_0
    maxi_0 = i
  elif s0[i] >= s0[maxi2_0]:
    maxi2_0 = i
maxi_1 = 0
maxi2_1 = 0
for i in range(100001):
  if s1[i] >= s1[maxi_1]:
    maxi2_1 = maxi_1
    maxi_1 = i
  elif s1[i] >= s1[maxi2_1]:
    maxi2_1 = i
if maxi_0 != maxi_1:
  print(n - s0[maxi_0] - s1[maxi_1])
else:
  print(n - max(s0[maxi_0] + s1[maxi2_1], s0[maxi2_0] + s1[maxi_1]))