Buggy python submission (verdict: Time Limit Exceeded):
import sys
input = sys.stdin.readline


h, w = map(int, input().split())
A = []
B = []

for i in range(h):
    line = list(map(int, input().split()))
    A.append(line)

for i in range(h):
    line = list(map(int, input().split()))
    B.append(line)


def slide_down(y, x, possible):
    new = set()
    delta = abs(A[y+1][x] - B[y+1][x])
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


def slide_right(y, x, possible):
    new = set()
    delta = abs(A[y][x+1] - B[y][x+1])
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


DP = [[set() for j in range(w)] for i in range(h)]
DP[0][0] = {abs(A[0][0] - B[0][0])}
for row in range(h):
    for col in range(w):
        possible = DP[row][col]
        if col < w-1:
            new = slide_right(row, col, possible)
            DP[row][col+1] |= new
        if row < h-1:
            new = slide_down(row, col, possible)
            DP[row+1][col] |= new

ans = min(DP[h-1][w-1])
print(ans)

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


h, w = map(int, input().split())
inf = float('INF')
A = []
B = []

for i in range(h):
    line = list(map(int, input().split()))
    A.append(line)

for i in range(h):
    line = list(map(int, input().split()))
    B.append(line)

D = [[0]*w for i in range(h)]
for i in range(h):
    for j in range(w):
        D[i][j] = abs(A[i][j] - B[i][j])


def slide_down(y, x, possible):
    new = set()
    delta = D[y+1][x]
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


def slide_right(y, x, possible):
    new = set()
    delta = D[y][x+1]
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


DP = [[set() for j in range(w)] for i in range(h)]
DP[0][0] = {D[0][0]}
for row in range(h):
    for col in range(w):
        possible = DP[row][col]
        if col < w-1:
            new = slide_right(row, col, possible)
            DP[row][col+1] |= new
        if row < h-1:
            new = slide_down(row, col, possible)
            DP[row+1][col] |= new

ans = min(DP[h-1][w-1])
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
h, w = map(int, input().split())
inf = float('INF')
A = []
B = []

for i in range(h):
    line = list(map(int, input().split()))
    A.append(line)

for i in range(h):
    line = list(map(int, input().split()))
    B.append(line)

D = [[0]*w for i in range(h)]
for i in range(h):
    for j in range(w):
        D[i][j] = abs(A[i][j] - B[i][j])


def slide_down(y, x, possible: set):
    new = set()
    delta = D[y+1][x]
    for num in possible:
        if num + delta <=6400:
            new.add(num+delta)
        if abs(num-delta) <= 6400:
            new.add(abs(num-delta))
    return new


def slide_right(y, x, possible: set):
    new = set()
    delta = D[y][x+1]
    for num in possible:
        if num + delta <=6400:
            new.add(num+delta)
        if abs(num-delta) <=6400:
            new.add(abs(num-delta))
    return new


DP = [[set() for j in range(w)] for i in range(h)]
DP[0][0] = {D[0][0]}
for row in range(h):
    for col in range(w):
        possible = DP[row][col]
        if col < w-1:
            new = slide_right(row, col, possible)
            DP[row][col+1] |= new
        if row < h-1:
            new = slide_down(row, col, possible)
            DP[row+1][col] |= new

ans = min(DP[h-1][w-1])
print(ans)


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


h, w = map(int, input().split())
inf = float('INF')
A = []
B = []

for i in range(h):
    line = list(map(int, input().split()))
    A.append(line)

for i in range(h):
    line = list(map(int, input().split()))
    B.append(line)

D = [[0]*w for i in range(h)]
for i in range(h):
    for j in range(w):
        D[i][j] = abs(A[i][j] - B[i][j])


def slide_down(y, x, possible):
    new = set()
    delta = D[y+1][x]
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


def slide_right(y, x, possible):
    new = set()
    delta = D[y][x+1]
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


DP = [[set() for j in range(w)] for i in range(h)]
DP[0][0] = {D[0][0]}
for row in range(h):
    for col in range(w):
        possible = DP[row][col]
        if col < w-1:
            new = slide_right(row, col, possible)
            DP[row][col+1] |= new
        if row < h-1:
            new = slide_down(row, col, possible)
            DP[row+1][col] |= new

ans = min(DP[h-1][w-1])
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
h, w = map(int, input().split())
inf = float('INF')
A = []
B = []

for i in range(h):
    line = list(map(int, input().split()))
    A.append(line)

for i in range(h):
    line = list(map(int, input().split()))
    B.append(line)

D = [[0]*w for i in range(h)]
for i in range(h):
    for j in range(w):
        D[i][j] = abs(A[i][j] - B[i][j])


def slide_down(y, x, possible: set):
    new = set()
    delta = D[y+1][x]
    for num in possible:
        if num + delta <=16000:
            new.add(num+delta)
        if abs(num-delta) <= 16000:
            new.add(abs(num-delta))
    return new


def slide_right(y, x, possible: set):
    new = set()
    delta = D[y][x+1]
    for num in possible:
        if num + delta <=16000:
            new.add(num+delta)
        if abs(num-delta) <=16000:
            new.add(abs(num-delta))
    return new


DP = [[set() for j in range(w)] for i in range(h)]
DP[0][0] = {D[0][0]}
for row in range(h):
    for col in range(w):
        possible = DP[row][col]
        if col < w-1:
            new = slide_right(row, col, possible)
            DP[row][col+1] |= new
        if row < h-1:
            new = slide_down(row, col, possible)
            DP[row+1][col] |= new

ans = min(DP[h-1][w-1])
print(ans)

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


h, w = map(int, input().split())
inf = float('INF')
A = []
B = []

for i in range(h):
    line = list(map(int, input().split()))
    A.append(line)

for i in range(h):
    line = list(map(int, input().split()))
    B.append(line)

D = [[0]*w for i in range(h)]
for i in range(h):
    for j in range(w):
        D[i][j] = abs(A[i][j] - B[i][j])


def slide_down(y, x, possible):
    new = set()
    delta = D[y+1][x]
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


def slide_right(y, x, possible):
    new = set()
    delta = D[y][x+1]
    limit = (h+w) * 80
    for num in possible:
        if num + delta <= limit - (y+x)*80:
            new.add(num+delta)
        if abs(num-delta) <= limit - (y+x)*80:
            new.add(abs(num-delta))
    return new


DP = [[set() for j in range(w)] for i in range(h)]
DP[0][0] = {D[0][0]}
for row in range(h):
    for col in range(w):
        possible = DP[row][col]
        if col < w-1:
            new = slide_right(row, col, possible)
            DP[row][col+1] |= new
        if row < h-1:
            new = slide_down(row, col, possible)
            DP[row+1][col] |= new

ans = min(DP[h-1][w-1])
print(ans)