class A:
    def __init__(self, txt: str):
        self.r: D = None
        self.w: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.u: B = None
        self.p: B = None
        self.x: B = None
        self.s: E = None
        self.v: A = None
        self.o: A = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.q: A = None
        self.w: A = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.u: B = None
        self.p: B = None
        self.x: B = None
        self.s: E = None
        self.v: A = None
        self.o: A = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.q: A = None
        self.w: A = None
        self.txt = txt

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

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