Buggy python submission (verdict: Runtime Error):
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, bin(x).count('1'))
print(ans)



Fixed submission:
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x):
    ret = 0
    while x>0:
        ret += x & 1
        x <<= 1
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)



Fixed submission:
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x):
    ret = 0
    while x>0:
        ret += x & 1
        x <<= 1
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Fixed submission:
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return(ret)

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(i):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Fixed submission:
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return(ret)

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(i):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Fixed submission:
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return(ret)

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(i):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)

Fixed submission:
n = int(input())
xys = [[] for _ in range(n)]
for i in range(n):
    a = int(input())
    for j in range(a):
        x, y = map(int, input().split())
        xys[i].append((x-1, y))

def digitsum(x, base=2):
    ret = 0
    while x>0:
        ret += x % base
        x = x // base
    return ret

ans = 0
for i in range(1<<n):
    ok = True
    for j in range(n):
        # if jth person may be honest, verify testimony of him.
        if (i>>j) & 1 == 1:
            for xy in xys[j]:
                x, y = xy
                if (i>>x) & 1 != y:
                    ok = False
                    break
        if not ok:
            break
    if ok:
        ans = max(ans, digitsum(i))
print(ans)