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)

from collections import Counter
import sys

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

A = V[0::2]
B = V[1::2]

# print(A, B)

cnt = 0

if len(set(V)) == 1:
    print(N // 2)
    sys.exit()


def get_keys_from_value(d, val):
    return [k for k, v in d.items() if v == val]


if set(A) != 1:
    cnt += len(A) - max(Counter(A).values())
if set(B) != 1:
    if A == B:
        need_to_be_changed = get_keys_from_value(Counter(B), max(Counter(A).values()))
        need_to_be_changed_num = Counter(B)[need_to_be_changed[0]]
        cnt += need_to_be_changed_num
    else:
        cnt += len(B) - max(Counter(B).values())

print(cnt)