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

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

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

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

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

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

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

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

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

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

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

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

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

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

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