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

class B:
    def __init__(self, txt: str):
        self.w: F = None
        self.o: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: B = None
        self.q: C = None
        self.z: C = None
        self.t: F = None
        self.s: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: C = None
        self.t: B = None
        self.u: C = None
        self.y: D = None
        self.q: D = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.w: F = None
        self.o: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: B = None
        self.q: C = None
        self.z: C = None
        self.t: F = None
        self.s: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: C = None
        self.t: B = None
        self.u: C = None
        self.y: D = None
        self.q: D = None
        self.txt = txt

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

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