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 PyPy3 (2.4.0) (judge verdict: Accepted)

import itertools
import math
import fractions
import functools
l = [0]*(10**5+10)
r = [0]*(10**5+10)

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

for i in range(n):
    if i % 2 == 0:
        l[v[i]] += 1
    else:
        r[v[i]] += 1

max_l = l.index(max(l))
max_r = r.index(max(r))
count = 0

if max_l == max_r:
    for i in range(len(r)):
        if r[i] == r[max_r]:
            r[i] = 0
        if l[i] == l[max_l]:
            l[i] = 0
if max(l) > max(r):
    max_l = l.index(max(l))
else:
    max_r = r.index(max(r))

for i in range(n):
    if i % 2 == 0 and v[i] != max_l:
        count += 1
    if i % 2 != 0 and v[i] != max_r:
        count += 1
print(count)