Buggy python submission (verdict: Runtime Error):
import collections as col
from functools import reduce
from operator import add
n = int(input())

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

if len(set(v)) == 1:
    print(int(n / 2))
    exit()

odd = v[1::2]
even = v[0::2]

co = col.Counter(odd).most_common()
coli = list(co.values())
ce = col.Counter(even).most_common()
celi = list(ce.values())

cov = list(co.keys())
cev = list(ce.keys())

if cov[0] != cev[0]:
    a = reduce(add, coli[1:], 0)
    b = reduce(add, celi[1:], 0)
    print(n - coli[0] - coli[0])
else:
    # a1 = reduce(add, coli[1:], 0)
    # b1 = reduce(add, celi[2:], 0)
    # b1 = celi[0] + b1

    # a2 = reduce(add, coli[2:], 0)
    # b2 = reduce(add, celi[1:], 0)
    # a2 = a2 + coli[0]
    if len(coli) <= 1:
        coli.append(0)
    if len(celi) <= 1:
        celi.append(0)

    ans1 = n - coli[1] - celi[0]
    ans2 = n - coli[0] - celi[1]

    print(min(ans1, ans2))

Fixed submission:
import collections as col
from functools import reduce
from operator import add
n = int(input())

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

if len(set(v)) == 1:
    print(int(n / 2))
    exit()

odd = v[1::2]
even = v[0::2]

co = col.Counter(odd).most_common()
ce = col.Counter(even).most_common()

if co[0][0] != ce[0][0]:
    print(n - co[0][1] - ce[0][1])
else:
    # a1 = reduce(add, coli[1:], 0)
    # b1 = reduce(add, celi[2:], 0)
    # b1 = celi[0] + b1

    # a2 = reduce(add, coli[2:], 0)
    # b2 = reduce(add, celi[1:], 0)
    # a2 = a2 + coli[0]
    if len(co) <= 1:
        co.append((0, 0))
    if len(ce) <= 1:
        ce.append((0, 0))

    ans1 = n - co[1][1] - ce[0][1]
    ans2 = n - co[0][1] - ce[1][1]

    print(min(ans1, ans2))

Buggy python submission (verdict: Runtime Error):
import collections as col
from functools import reduce
from operator import add
n = int(input())

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

# if len(set(v)) == 1:
#     print(int(n / 2))
#     exit()

odd = v[1::2]
even = v[0::2]

co = col.Counter(odd)
coli = list(co.values())
ce = col.Counter(even)
celi = list(ce.values())

cov = list(co.keys())
cev = list(ce.keys())

if cov[0] != cev[0]:
    a = reduce(add, coli[1:], 0)
    b = reduce(add, celi[1:], 0)
    print(a + b)
else:
    # a1 = reduce(add, coli[1:], 0)
    # b1 = reduce(add, celi[2:], 0)
    # b1 = celi[0] + b1

    # a2 = reduce(add, coli[2:], 0)
    # b2 = reduce(add, celi[1:], 0)
    # a2 = a2 + coli[0]
    ans1 = n - coli[1] - celi[0]
    ans2 = n - coli[0] - celi[1]

    print(min(ans1, ans2))

Fixed submission:
import collections as col
from functools import reduce
from operator import add
n = int(input())

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

if len(set(v)) == 1:
    print(int(n / 2))
    exit()

odd = v[1::2]
even = v[0::2]

co = col.Counter(odd).most_common()
ce = col.Counter(even).most_common()

if co[0][0] != ce[0][0]:
    print(n - co[0][1] - ce[0][1])
else:
    # a1 = reduce(add, coli[1:], 0)
    # b1 = reduce(add, celi[2:], 0)
    # b1 = celi[0] + b1

    # a2 = reduce(add, coli[2:], 0)
    # b2 = reduce(add, celi[1:], 0)
    # a2 = a2 + coli[0]
    if len(co) <= 1:
        co.append((0, 0))
    if len(ce) <= 1:
        ce.append((0, 0))

    ans1 = n - co[1][1] - ce[0][1]
    ans2 = n - co[0][1] - ce[1][1]

    print(min(ans1, ans2))