Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import bisect as br, bisect_left as bl
readline = sys.stdin.readline

N = int(readline())
A = list(map(int, readline().split()))
B = list(map(int, readline().split()))
A.sort()
B.sort()
cnta = [0]*29
cntb = [0]*29
for idx in range(N):
    a, b = A[idx], B[idx]
    for i in range(29):
        if (1<<i) & a:
            cnta[i] = 1 - cnta[i]
        if (1<<i) & b:
            cntb[i] = 1 - cntb[i]

carry = [0]*30
bwa = [0]*N
bwb = [0]*N
for i in range(29):
    for idx in range(N):
        if (1<<i) & B[idx]:
            bwb[idx] |= 1<<i
    bwbc = sorted(bwb)
    m = (1<<(i+1))-1
    for idx in range(N):
        a = A[idx]&m 
        carry[i+1] += (N - bl(bwbc, m+1 if a == 0 else m&(-a)))%2
        
ans = 0
for i in range(29):
    if (carry[i] + (cnta[i]+cntb[i])*N) % 2 == 1:
        ans |= 1<<i
print(ans)

Fixed submission:
import sys
readline = sys.stdin.readline

N = int(readline())
A = list(map(int, readline().split()))
B = list(map(int, readline().split()))
A.sort()
B.sort()
cnta = [0]*29
cntb = [0]*29
for idx in range(N):
    a, b = A[idx], B[idx]
    for i in range(29):
        if (1<<i) & a:
            cnta[i] = 1 - cnta[i]
        if (1<<i) & b:
            cntb[i] = 1 - cntb[i]

carry = [0]*30
bwa = [0]*N
bwb = [0]*N
for i in range(29):
    m = (1<<(i+1))-1
    bwbc = sorted([b&m for b in B])
    bwac = sorted([m+1 if a&m == 0 else m&(-(a&m)) for a in A])
    r = N
    for idx in range(N-1, -1, -1):
        a = bwac[idx]
        while r and bwbc[r-1] >= a:
            r -= 1
        carry[i+1] += N - r
        
ans = 0
for i in range(29):
    if (carry[i] + (cnta[i]+cntb[i])*N) % 2 == 1:
        ans |= 1<<i
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import sys
from bisect import bisect as br, bisect_left as bl
readline = sys.stdin.readline

N = int(readline())
A = list(map(int, readline().split()))
B = list(map(int, readline().split()))
A.sort()
B.sort()
cnta = [0]*30
cntb = [0]*30
for idx in range(N):
    a, b = A[idx], B[idx]
    for i in range(30):
        if (1<<i) & a:
            cnta[i] += 1
        if (1<<i) & b:
            cntb[i] += 1

carry = [0]*31
bwa = [0]*N
bwb = [0]*N
for i in range(30):
    for idx in range(N):
        if (1<<i) & A[idx]:
            bwa[idx] |= 1<<i
        if (1<<i) & B[idx]:
            bwb[idx] |= 1<<i
    bwbc = sorted(bwb)
    m = (1<<(i+1))-1
    for idx in range(N):
        a = bwa[idx]
        carry[i+1] += N - bl(bwbc, m+1 if a == 0 else m&(-a))
        
ans = 0
for i in range(30):
    ca = cnta[i]
    cb = cntb[i]
    if (carry[i] + ca*(N-cb) + (N-ca)*cb) % 2 == 1:
        ans |= 1<<i
print(ans)

Fixed submission:
import sys
readline = sys.stdin.readline

N = int(readline())
A = list(map(int, readline().split()))
B = list(map(int, readline().split()))
A.sort()
B.sort()
cnta = [0]*29
cntb = [0]*29
for idx in range(N):
    a, b = A[idx], B[idx]
    for i in range(29):
        if (1<<i) & a:
            cnta[i] = 1 - cnta[i]
        if (1<<i) & b:
            cntb[i] = 1 - cntb[i]

carry = [0]*30
bwa = [0]*N
bwb = [0]*N
for i in range(29):
    m = (1<<(i+1))-1
    bwbc = sorted([b&m for b in B])
    bwac = sorted([m+1 if a&m == 0 else m&(-(a&m)) for a in A])
    r = N
    for idx in range(N-1, -1, -1):
        a = bwac[idx]
        while r and bwbc[r-1] >= a:
            r -= 1
        carry[i+1] += N - r
        
ans = 0
for i in range(29):
    if (carry[i] + (cnta[i]+cntb[i])*N) % 2 == 1:
        ans |= 1<<i
print(ans)