Krestiki-noliki

def vivod():
    for i in range(3):
        print(field[i][0],field[i][1],field[i][2])



def change(xo):
    loc = int(input('Введите кординату "{}": '.format(xo)))
    gor = loc//3
    ver = loc%3
    if type(field[gor][ver])==str:
        return 0
    field[gor][ver]=xo

field=[
    [0,1,2],
    [3,4,5],
    [6,7,8]
    ]


flag = 0
while flag == 0:
    vivod()
    #ходят крестики
    while change('x')==0:
        print('Введите другую кординату! ')
    for y in range(3):
        sum =0
        for x in range(3):
            if field[y][x]=='x':
                sum+=1
            elif field[y][x]=='o':
                sum-=1
        if sum==3:
            print('POBEDA KRESTIKOV')
            flag=1
        elif sum==-3:
            print('POBEDA NOLIKOV')
            flag=1


    for x in range(3):
        sum =0
        for y in range(3):
            if field[y][x]=='x':
                sum+=1
            elif field[y][x]=='o':
                sum-=1
        if sum==3:
            print('POBEDA KRESTIKOV')
            flag=1
        elif sum==-3:
            print('POBEDA NOLIKOV')
            flag=1

    if (field[0][0]==field[1][1] and field[1][1]==field[2][2] and field[1][1]=='x') or (field[2][0]==field[1][1] and field[1][1]==field[0][2] and field[1][1]=='x'):
        print('POBEDA KRESTIKOV')
        flag=1
    elif (field[0][0]==field[1][1] and field[1][1]==field[2][2] and field[1][1]=='o') or (field[2][0]==field[1][1] and field[1][1]==field[0][2] and field[1][1]=='o'):
        print('POBEDA NOLIKOV')
        flag=1



    #ходят нолики
    if flag==0:
        vivod()
        while change('o')==0:
            print('Введите другую кординату! ')
        for y in range(3):
            sum =0
            for x in range(3):
                if field[y][x]=='x':
                    sum+=1
                elif field[y][x]=='o':
                    sum-=1
            if sum==3:
                print('POBEDA KRESTIKOV')
                flag=1
            elif sum==-3:
                print('POBEDA NOLIKOV')
                flag=1


        for x in range(3):
            sum =0
            for y in range(3):
                if field[y][x]=='x':
                    sum+=1
                elif field[y][x]=='o':
                    sum-=1
            if sum==3:
                print('POBEDA KRESTIKOV')
                flag=1
            elif sum==-3:
                print('POBEDA NOLIKOV')
                flag=1

        if (field[0][0]==field[1][1] and field[1][1]==field[2][2] and field[1][1]=='x') or (field[2][0]==field[1][1] and field[1][1]==field[0][2] and field[1][1]=='x'):
            print('POBEDA KRESTIKOV')
            flag=1
        elif (field[0][0]==field[1][1] and field[1][1]==field[2][2] and field[1][1]=='o') or (field[2][0]==field[1][1] and field[1][1]==field[0][2] and field[1][1]=='o'):
            print('POBEDA NOLIKOV')
            flag=1