Buggy python submission (verdict: Time Limit Exceeded):
from itertools import permutations
import collections
N = int(input())
nums = list(map(int, input().split()))
odd_nums = []
even_nums = []
for i, num in enumerate(nums):
    if i % 2 == 1:
        even_nums.append(num)
    else:
        odd_nums.append(num)

useable_nums = set(nums)
even_length = len(even_nums)
odd_length = len(odd_nums)
even_counter = collections.Counter(even_nums)
odd_counter = collections.Counter(odd_nums)
# print(even_counter)  # 偶数
# print(odd_counter)  # 奇数
inf = float('inf')
min_ans = inf
if len(useable_nums) == 1:
    useable_nums.add(0)
useable_permutaions = list(permutations(useable_nums, 2))
# print(useable_permutaions)

for permutation in useable_permutaions:
    ans = 0
    if permutation[0] in odd_counter:
        ans += odd_length - odd_counter[permutation[0]]
    else:
        ans += odd_length
    if permutation[1] in even_counter:
        ans += even_length - even_counter[permutation[1]]
    else:
        ans += even_length
    min_ans = min(min_ans, ans)

print(min_ans)


Fixed submission:
from itertools import permutations
import collections
N = int(input())
nums = list(map(int, input().split()))
odd_nums = []
even_nums = []
for i, num in enumerate(nums):
    if i % 2 == 1:
        even_nums.append(num)
    else:
        odd_nums.append(num)

useable_nums = set(nums)
even_length = len(even_nums)
odd_length = len(odd_nums)
even_counter = collections.Counter(even_nums).most_common()
odd_counter = collections.Counter(odd_nums).most_common()
even_counter.append((0, 0))
odd_counter.append((0, 0))
even_counter.sort(key=lambda x: x[1], reverse=True)
odd_counter.sort(key=lambda x: x[1], reverse=True)
# print(even_counter)
# print(odd_counter)


min_ans = None
if even_counter[0][0] == odd_counter[0][0]:
    min_ans = min((odd_length - odd_counter[0][1]) + (even_length - even_counter[1][1]),
                  (odd_length - odd_counter[1][1]) + (even_length - even_counter[0][1]))
else:

    min_ans = odd_length - odd_counter[0][1] + even_length - even_counter[0][1]
print(min_ans)

Buggy python submission (verdict: Time Limit Exceeded):
from itertools import permutations
N = int(input())
nums = list(map(int, input().split()))

useable_nums = set(nums)

# print(nums)
# print(useable_nums)

inf = float('inf')
min_ans = inf
if len(useable_nums) == 1:
    useable_nums.add(list(useable_nums)[0] + 1)
useable_permutaions = permutations(useable_nums, 2)
# print(useable_permutaions)
# print(list(useable_permutaions))
# print(list(useable_permutaions))
for permutation in useable_permutaions:
    ans = 0
    for i, num in enumerate(nums):
        if i % 2 == 0:
            if permutation[0] != num:
                # print(num, i, permutation[0])
                ans += 1
        else:
            if permutation[1] != num:
                # print(num, i, permutation[1])
                ans += 1
    # print(permutation, ans)
    min_ans = min(min_ans, ans)

print(min_ans)


Fixed submission:
from itertools import permutations
import collections
N = int(input())
nums = list(map(int, input().split()))
odd_nums = []
even_nums = []
for i, num in enumerate(nums):
    if i % 2 == 1:
        even_nums.append(num)
    else:
        odd_nums.append(num)

useable_nums = set(nums)
even_length = len(even_nums)
odd_length = len(odd_nums)
even_counter = collections.Counter(even_nums).most_common()
odd_counter = collections.Counter(odd_nums).most_common()
even_counter.append((0, 0))
odd_counter.append((0, 0))
even_counter.sort(key=lambda x: x[1], reverse=True)
odd_counter.sort(key=lambda x: x[1], reverse=True)
# print(even_counter)
# print(odd_counter)


min_ans = None
if even_counter[0][0] == odd_counter[0][0]:
    min_ans = min((odd_length - odd_counter[0][1]) + (even_length - even_counter[1][1]),
                  (odd_length - odd_counter[1][1]) + (even_length - even_counter[0][1]))
else:

    min_ans = odd_length - odd_counter[0][1] + even_length - even_counter[0][1]
print(min_ans)