class A:
    def __init__(self, txt: str):
        self.z: B = None
        self.s: E = None
        self.x: E = None
        self.o: C = None
        self.txt = txt

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: E = None
        self.txt = txt

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

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: E = None
        self.txt = txt

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

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