Buggy python submission (verdict: Runtime Error):
import collections

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

hantei = 0

for i in range(0,n):
    if u[0] != u[i]:
        hantei = 1
        break

if hantei == 0:
    print(n // 2)
else:
   u1 = [] 
   u2 = [] 
   ans = 0
   for j in range(n):
       if j % 2 == 0:
           u2.append(u[j])
       else:
           u1.append(u[j])
   u1_list =collections.Counter(u1)
   u2_list =collections.Counter(u2)
   values1, counts1 = u1_list.most_common()[0]
   values2, counts2 = u2_list.most_common()[0]
   if values1 != values2:
       ans += n // 2 - counts1
       ans += n // 2 - counts2
   else:
       if len(u1_list) > 1 and len(u2_list) > 1:
           values3, counts3 = u1_list.most_common()[0]
           values4, counts4 = u2_list.most_common()[0]
           ans1 = n - count1 - count4
           ans2 = n - count2 - count3
           ans = min(ans1,ans2)
       elif len(u1_list) > 1 and len(u2_list) < 2:
           values3, counts3 = u1_list.most_common()[0]
           ans = n - count2 - count3
       elif len(u1_list) < 2 and len(u2_list) > 1:
           values3, counts3 = u2_list.most_common()[0]
           ans = n - count1 - count3

       ans = min(ans1,ans2)
   print(ans)

Fixed submission:
import collections

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

hantei = 0

for i in range(0,n):
    if u[0] != u[i]:
        hantei = 1
        break

if hantei == 0:
    print(n // 2)
else:
   u1 = [] 
   u2 = [] 
   ans = 0
   for j in range(n):
       if j % 2 == 0:
           u2.append(u[j])
       else:
           u1.append(u[j])
   u1_list =collections.Counter(u1)
   u2_list =collections.Counter(u2)
   values1, counts1 = u1_list.most_common()[0]
   values2, counts2 = u2_list.most_common()[0]
   if values1 != values2:
       ans += n // 2 - counts1
       ans += n // 2 - counts2
   else:
       if len(u1_list) > 1 and len(u2_list) > 1:
           values3, counts3 = u1_list.most_common()[1]
           values4, counts4 = u2_list.most_common()[1]
           ans1 = n - counts1 - counts4
           ans2 = n - counts2 - counts3
           ans = max(ans1,ans2)
       elif len(u1_list) > 1 and len(u2_list) < 2:
           values3, counts3 = u1_list.most_common()[1]
           ans = n - counts2 - counts3
       elif len(u1_list) < 2 and len(u2_list) > 1:
           values3, counts3 = u2_list.most_common()[1]
           ans = n - counts1 - counts3

       ans = min(ans1,ans2)
   print(ans)

Buggy python submission (verdict: Runtime Error):
import collections

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

hantei = 0

for i in range(1,n):
    if u[0] != u[i]:
        hantei = 1
        break

if hantei == 0:
    print(n // 2)
else:
   u1 = [] 
   u2 = [] 
   ans = 0
   for j in range(n):
       if j % 2 == 0:
           u2.append(u[j])
       else:
   u1_list =collections.Counter(u1)
   u2_list =collections.Counter(u2)
   values1, counts1 = u1_list.most_common()[0]
   values2, counts2 = u2_list.most_common()[0]
   ans += n // 2 - counts1
   ans += n // 2 - counts2
   print(ans)

Fixed submission:
import collections

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

hantei = 0

for i in range(0,n):
    if u[0] != u[i]:
        hantei = 1
        break

if hantei == 0:
    print(n // 2)
else:
   u1 = [] 
   u2 = [] 
   ans = 0
   for j in range(n):
       if j % 2 == 0:
           u2.append(u[j])
       else:
           u1.append(u[j])
   u1_list =collections.Counter(u1)
   u2_list =collections.Counter(u2)
   values1, counts1 = u1_list.most_common()[0]
   values2, counts2 = u2_list.most_common()[0]
   if values1 != values2:
       ans += n // 2 - counts1
       ans += n // 2 - counts2
   else:
       if len(u1_list) > 1 and len(u2_list) > 1:
           values3, counts3 = u1_list.most_common()[1]
           values4, counts4 = u2_list.most_common()[1]
           ans1 = n - counts1 - counts4
           ans2 = n - counts2 - counts3
           ans = max(ans1,ans2)
       elif len(u1_list) > 1 and len(u2_list) < 2:
           values3, counts3 = u1_list.most_common()[1]
           ans = n - counts2 - counts3
       elif len(u1_list) < 2 and len(u2_list) > 1:
           values3, counts3 = u2_list.most_common()[1]
           ans = n - counts1 - counts3

       ans = min(ans1,ans2)
   print(ans)