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

class B:
    def __init__(self, txt: str):
        self.w: C = None
        self.y: A = None
        self.q: A = None
        self.v: F = None
        self.u: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.p: D = None
        self.z: A = None
        self.o: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.t: A = None
        self.r: B = None
        self.z: A = None
        self.u: B = None
        self.s: B = None
        self.y: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: C = None
        self.txt = txt

j = A("j")
f = B("f")
l = C("l")
i = D("i")
b = E("b")
e = F("e")

j.t = b
j.z = b
j.s = e
j.v = e
j.r = i
j.p = l
f.w = l
f.y = j
f.q = j
f.v = e
f.u = i
l.p = i
l.z = j
l.o = e
i.y = e
b.t = j
b.z = j
b.r = f
b.u = f
b.s = f
b.y = e
e.t = l
assert i.y.t.p.y.txt == "
class A:
    def __init__(self, txt: str):
        self.t: E = None
        self.s: F = None
        self.z: E = None
        self.r: D = None
        self.v: F = None
        self.p: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.w: C = None
        self.y: A = None
        self.q: A = None
        self.v: F = None
        self.u: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.p: D = None
        self.z: A = None
        self.o: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.t: A = None
        self.r: B = None
        self.z: A = None
        self.u: B = None
        self.s: B = None
        self.y: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: C = None
        self.txt = txt

j = A("j")
f = B("f")
l = C("l")
i = D("i")
b = E("b")
e = F("e")

j.t = b
j.z = b
j.s = e
j.v = e
j.r = i
j.p = l
f.w = l
f.y = j
f.q = j
f.v = e
f.u = i
l.p = i
l.z = j
l.o = e
i.y = e
b.t = j
b.z = j
b.r = f
b.u = f
b.s = f
b.y = e
e.t = l
assert i.y.t.p.y.txt == "e"