class A:
    def __init__(self, txt: str):
        self.s: E = None
        self.y: F = None
        self.v: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: D = None
        self.s: D = None
        self.q: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: A = None
        self.u: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: A = None
        self.z: E = None
        self.r: B = None
        self.q: C = None
        self.s: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.w: E = None
        self.z: A = None
        self.s: A = None
        self.o: A = None
        self.p: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: B = None
        self.z: E = None
        self.u: D = None
        self.t: A = None
        self.v: F = None
        self.x: B = None
        self.txt = txt

b = A("b")
l = B("l")
n = C("n")
c = D("c")
a = E("a")
m = F("m")
e = E("e")
d = F("d")
f = B("f")

b.s = a
b.y = m
b.v = n
l.y = c
l.s = c
l.q = m
n.r = b
n.u = f
c.p = b
c.z = e
c.r = f
c.q = n
c.s = l
a.w = e
a.z = b
a.s = b
a.o = b
a.p = b
m.q = l
m.x = l
m.z = a
m.u = c
m.t = b
m.v = d
e.w = a
e.z = b
e.s = b
e.o = b
e.p = b
d.q = l
d.z = a
d.u = c
d.t = b
d.v = m
d.x = f
f.y = c
f.s = c
f.q = d
assert a.w.w.w.s.y.v.z.txt == "
class A:
    def __init__(self, txt: str):
        self.s: E = None
        self.y: F = None
        self.v: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: D = None
        self.s: D = None
        self.q: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: A = None
        self.u: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: A = None
        self.z: E = None
        self.r: B = None
        self.q: C = None
        self.s: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.w: E = None
        self.z: A = None
        self.s: A = None
        self.o: A = None
        self.p: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: B = None
        self.z: E = None
        self.u: D = None
        self.t: A = None
        self.v: F = None
        self.x: B = None
        self.txt = txt

b = A("b")
l = B("l")
n = C("n")
c = D("c")
a = E("a")
m = F("m")
e = E("e")
d = F("d")
f = B("f")

b.s = a
b.y = m
b.v = n
l.y = c
l.s = c
l.q = m
n.r = b
n.u = f
c.p = b
c.z = e
c.r = f
c.q = n
c.s = l
a.w = e
a.z = b
a.s = b
a.o = b
a.p = b
m.q = l
m.x = l
m.z = a
m.u = c
m.t = b
m.v = d
e.w = a
e.z = b
e.s = b
e.o = b
e.p = b
d.q = l
d.z = a
d.u = c
d.t = b
d.v = m
d.x = f
f.y = c
f.s = c
f.q = d
assert a.w.w.w.s.y.v.z.txt == "a"