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)

import sys
input = sys.stdin.readline

N = int(input())
vvv = list(map(int, input().split()))

vvv_odd = vvv[::2]
vvv_even = vvv[1::2]

odd_vocab = set(vvv_odd)
even_vocab = set(vvv_even)


def calc_rewrite_number(vvv_each, vocab):
    max_count = -1
    for v in vocab:
        max_count = max(max_count, vvv_each.count(v))
    len_vvv_each = len(vvv_each)
    return len_vvv_each - max_count


# Calculation for odd and even elements in vvv
n_rewrite = 0
n_rewrite += calc_rewrite_number(vvv_odd, odd_vocab)
n_rewrite += calc_rewrite_number(vvv_even, even_vocab)
if len(odd_vocab & even_vocab) == 1:
    n_rewrite += len(vvv_odd)

# Output
print(n_rewrite)