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

class B:
    def __init__(self, txt: str):
        self.o: E = None
        self.q: B = None
        self.w: A = None
        self.x: F = None
        self.u: E = None
        self.r: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.z: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: E = None
        self.w: C = None
        self.t: C = None
        self.p: E = None
        self.o: F = None
        self.q: F = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.o: E = None
        self.q: B = None
        self.w: A = None
        self.x: F = None
        self.u: E = None
        self.r: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.z: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: E = None
        self.w: C = None
        self.t: C = None
        self.p: E = None
        self.o: F = None
        self.q: F = None
        self.txt = txt

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

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

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