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

class B:
    def __init__(self, txt: str):
        self.r: E = None
        self.y: C = None
        self.z: C = None
        self.v: C = None
        self.x: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: A = None
        self.z: F = None
        self.x: E = None
        self.w: B = None
        self.q: B = None
        self.y: E = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.r: E = None
        self.y: C = None
        self.z: C = None
        self.v: C = None
        self.x: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: A = None
        self.z: F = None
        self.x: E = None
        self.w: B = None
        self.q: B = None
        self.y: E = None
        self.txt = txt

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

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

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