Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
v = list(map(int,input().split()))
vodd = v[0::2]
veven = v[1::2]

set_vodd = list(set(vodd))
set_veven = list(set(veven))
cnt_vodd = [0] * len(set_vodd)
cnt_veven = [0] * len(set_veven)

if len(set_vodd) == 1 and set_vodd == set_veven:
    print(int(n/2))
else:
    for i in range(len(set_vodd)):
        cnt_vodd[i] = vodd.count(set_vodd[i])
    sort_cnt_vodd = sorted(cnt_vodd)
    ans_vodd = (n/2) - (sort_cnt_vodd[-1])

    for i in range(len(set_veven)):
        cnt_veven[i] = veven.count(set_veven[i])
    sort_cnt_veven = sorted(cnt_veven)
    ans_veven = (n/2) - (sort_cnt_veven[-1])
    
    print(int(ans_vodd) + int(ans_veven))

Fixed submission:
import collections

n = int(input())
v = list(map(int,input().split()))
vodd = v[0::2]
veven = v[1::2]

set_vodd = list(set(vodd))
set_veven = list(set(veven))
cnt_vodd = collections.Counter(vodd)
cnt_veven = collections.Counter(veven)

if len(set_vodd) == 1 and set_vodd == set_veven:
    print(n//2)
else:
    if cnt_vodd.most_common(1)[0][0] != cnt_veven.most_common(1)[0][0]:
        ans_vodd = (n//2)- cnt_vodd.most_common(1)[0][1]
        ans_veven = (n//2)- cnt_veven.most_common(1)[0][1]
        print(ans_vodd + ans_veven)
    elif len(set_vodd)>=2 and len(set_veven)>=2:
        ans_vodd_1 = (n//2)- cnt_vodd.most_common(1)[0][1]
        ans_veven_1 = (n//2)- cnt_veven.most_common(2)[1][1]
        ans_vodd_2 = (n//2)- cnt_vodd.most_common(2)[1][1]
        ans_veven_2 = (n//2)- cnt_veven.most_common(1)[0][1]
        print(min(ans_vodd_1+ans_veven_1,ans_vodd_2+ans_veven_2))

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
v = list(map(int,input().split()))
vodd = v[0::2]
veven = v[1::2]

set_vodd = list(set(vodd))
set_veven = list(set(veven))
cnt_vodd = [0] * len(set_vodd)
cnt_veven = [0] * len(set_veven)

if len(set_vodd) == 1 and set_vodd == set_veven:
    print(int(n/2))
else:
    for i in range(len(set_vodd)):
        cnt_vodd[i] = vodd.count(set_vodd[i])
    sort_cnt_vodd = sorted(cnt_vodd)
    ans_vodd = (n/2) - (sort_cnt_vodd[-1])

    for i in range(len(set_veven)):
        cnt_veven[i] = veven.count(set_veven[i])
    sort_cnt_veven = sorted(cnt_veven)
    ans_veven = (n/2) - (sort_cnt_veven[-1])
    
    print(int(ans_vodd) + int(ans_veven))

Fixed submission:
import collections

n = int(input())
v = list(map(int,input().split()))
vodd = v[0::2]
veven = v[1::2]

set_vodd = list(set(vodd))
set_veven = list(set(veven))
cnt_vodd = collections.Counter(vodd)
cnt_veven = collections.Counter(veven)

if len(set_vodd) == 1 and set_vodd == set_veven:
    print(n//2)
else:
    if cnt_vodd.most_common(1)[0][0] != cnt_veven.most_common(1)[0][0]:
        ans_vodd = (n//2)- cnt_vodd.most_common(1)[0][1]
        ans_veven = (n//2)- cnt_veven.most_common(1)[0][1]
        print(ans_vodd + ans_veven)
    elif len(set_vodd)>=2 and len(set_veven)>=2:
        ans_vodd_1 = (n//2)- cnt_vodd.most_common(1)[0][1]
        ans_veven_1 = (n//2)- cnt_veven.most_common(2)[1][1]
        ans_vodd_2 = (n//2)- cnt_vodd.most_common(2)[1][1]
        ans_veven_2 = (n//2)- cnt_veven.most_common(1)[0][1]
        print(min(ans_vodd_1+ans_veven_1,ans_vodd_2+ans_veven_2))