Buggy python submission (verdict: Time Limit Exceeded):
import sys
 
def kensho(x,tlist):
    for lis in tlist:
        if((x>>(lis[1]-1)) & 1 == lis[2]):
            pass
        else:
            return -1
 
    return bin(x).count('1')
 
 
def main():
    N = int(input())
    xy=[]
    ans=0
 
    for i in range(1,N+1):
        An= int(input())
        for j in range(0,An):
            x, y = map(int, input().split())
            xy.append([i,x,y])
 
    cnt = N
 
    tlist=[]
    for x in range (2 ** cnt):
        for y in range(cnt):
            if((x>>y) & 1):
                for z in xy:
                    if(z[0]==y+1):
                        tlist.append(z)
 
        anstack = kensho(x,tlist)
        if(ans<anstack):
            ans=anstack
 
        del tlist[:]
 
    print(ans)
 
main()

Fixed submission:
import sys

def kensho(x,tlist):
    for lis in tlist:
        if((x>>(lis[1]-1)) & 1 == lis[2]):
            pass
        else:
            return -1

    return bin(x).count('1')


def main():
    N = int(input())
    xy=[]
    ans=0

    for i in range(1,N+1):
        An= int(input())
        for j in range(0,An):
            x, y = map(int, input().split())
            xy.append([i,x,y])

    cnt = N

    tlist=[]
    for x in range (2 ** cnt):
        for y in range(cnt):
            if((x>>y) & 1):
                for z in xy:
                    if(z[0]==y+1):
                        tlist.append(z)

        anstack = kensho(x,tlist)
        if(ans<anstack):
            ans=anstack

        del tlist[:]

    print(ans)

main()

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


def kensho(x,tlist):
    for lis in tlist:
        if((x>>(lis[1]-1)) & 1 == lis[2]):
            pass
        else:
            return -1

    return bin(x).count('1')


def main():
    N = int(input())
    xy=[]
    ans=0

    for i in range(1,N+1):
        An= int(input())
        for j in range(0,An):
            x, y = map(int, input().split())
            xy.append([i,x,y])

    cnt = N

    tlist=[]
    for x in range (2 ** cnt):
        for y in range(cnt):
            if((x>>y) & 1):
                for z in xy:
                    if(z[0]==y+1):
                        tlist.append(z)

        anstack = kensho(x,tlist)
        if(ans<anstack):
            ans=anstack

        tlist.clear()

    print(ans)

main()

Fixed submission:
import sys

def kensho(x,tlist):
    for lis in tlist:
        if((x>>(lis[1]-1)) & 1 == lis[2]):
            pass
        else:
            return -1

    return bin(x).count('1')


def main():
    N = int(input())
    xy=[]
    ans=0

    for i in range(1,N+1):
        An= int(input())
        for j in range(0,An):
            x, y = map(int, input().split())
            xy.append([i,x,y])

    cnt = N

    tlist=[]
    for x in range (2 ** cnt):
        for y in range(cnt):
            if((x>>y) & 1):
                for z in xy:
                    if(z[0]==y+1):
                        tlist.append(z)

        anstack = kensho(x,tlist)
        if(ans<anstack):
            ans=anstack

        del tlist[:]

    print(ans)

main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


def kensho(x,tlist):
    for lis in tlist:
        if((x>>(lis[1]-1)) & 1 == lis[2]):
            pass
        else:
            return -1

    return bin(x).count('1')


def main():
    N = int(input())
    xy=[]
    ans=0

    for i in range(1,N+1):
        An= int(input())
        for j in range(0,An):
            x, y = map(int, input().split())
            xy.append([i,x,y])

    cnt = N

    tlist=[]
    for x in range (2 ** cnt):
        for y in range(cnt):
            if((x>>y) & 1):
                for z in xy:
                    if(z[0]==y+1):
                        tlist.append(z)

        anstack = kensho(x,tlist)
        if(ans<anstack):
            ans=anstack

        tlist.clear()

    print(ans)

main()

Fixed submission:
import sys

def kensho(x,tlist):
    for lis in tlist:
        if((x>>(lis[1]-1)) & 1 == lis[2]):
            pass
        else:
            return -1

    return bin(x).count('1')


def main():
    N = int(input())
    xy=[]
    ans=0

    for i in range(1,N+1):
        An= int(input())
        for j in range(0,An):
            x, y = map(int, input().split())
            xy.append([i,x,y])

    cnt = N

    tlist=[]
    for x in range (2 ** cnt):
        for y in range(cnt):
            if((x>>y) & 1):
                for z in xy:
                    if(z[0]==y+1):
                        tlist.append(z)

        anstack = kensho(x,tlist)
        if(ans<anstack):
            ans=anstack

        del tlist[:]

    print(ans)

main()