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: Runtime Error)

import collections as cole


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

v1 = v[::2]   #odd
v2 = v[1::2]  #even

d1 = cole.Counter(v1)
d2 = cole.Counter(v2)

values1, counts1 = zip(*d1.most_common())
values2, counts2 = zip(*d2.most_common())

max1 = values1[0]
max2 = values2[0]

if max1 == max2:
    if len(counts1) != 1 and counts1[0] == counts1[1]:
        max1 = values[1]
    elif len(counts2) != 1 and counts2[0] == counts[1]:
        max2 = values[1]
    elif len(counts1) != 1 and len(counts2) != 1:
        if counts1[1] > counts2[1]:
            max1 = values1[1]
        else:
            max2 = values2[1]
    elif len(counts1) != 1:
        max1 = values1[1]
    elif len(counts2) != 1:
        max2 = values2[1]

print(max1, max2)
count = 0
if max1 != max2:
    count += len([x for x in v1 if x != max1])
    count += len([y for y in v2 if y != max2])

else:
    count += len(v1)


print(count)