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

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

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

class D:
    def __init__(self, txt: str):
        self.y: F = None
        self.s: B = None
        self.u: A = None
        self.p: F = None
        self.t: C = None
        self.x: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: F = None
        self.t: D = None
        self.o: D = None
        self.x: D = None
        self.v: B = None
        self.r: D = None
        self.txt = txt

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.y: F = None
        self.s: B = None
        self.u: A = None
        self.p: F = None
        self.t: C = None
        self.x: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: F = None
        self.t: D = None
        self.o: D = None
        self.x: D = None
        self.v: B = None
        self.r: D = None
        self.txt = txt

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

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

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