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)

def getMode(target:list):
    cache = {}
    for x in target:
        if x in cache:
            cache[x] = cache[x] + 1
        else:
            cache[x] = 1
    return sorted(cache.items(), key=lambda x: x[1], reverse=True)


n = int(input())
v = [int(x) for x in input().split()]

guu = []
ki = []
for i, n in enumerate(v):
    if i % 2 == 0:
        guu.append(n)
    else:
        ki.append(n)

gMode = getMode(guu)
g = gMode[0][0]
kMode = getMode(ki)
k = kMode[0][0]

if g == k:
    if len(gMode) == 1:
        if len(kMode) == 1:
            k = g + 1
        else:
            k = kMode[1][0]
    elif len(kMode) == 1:
        g = gMode[1][0]
    else:
        if gMode[0][1] < kMode[0][1]:
            g = gMode[1][0]
        else:
            k = kMode[1][0]

result = 0
for n in guu:
    if n != g:
        result += 1

for n in ki:
    if n!= k:
        result += 1

print(result)