class A:
    def __init__(self, txt: str):
        self.s: I = None
        self.v: I = None
        self.o: C = None
        self.w: E = None
        self.t: E = None
        self.txt = txt

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.t: E = None
        self.p: E = None
        self.q: I = None
        self.s: A = None
        self.w: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.o: D = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.o: B = None
        self.s: D = None
        self.p: H = None
        self.t: D = None
        self.txt = txt

c = A("c")
j = B("j")
h = C("h")
a = D("a")
f = E("f")
d = F("d")
b = G("b")
l = H("l")
n = I("n")
e = E("e")

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.x: D = None
        self.t: E = None
        self.p: E = None
        self.q: I = None
        self.s: A = None
        self.w: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.o: D = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.o: B = None
        self.s: D = None
        self.p: H = None
        self.t: D = None
        self.txt = txt

c = A("c")
j = B("j")
h = C("h")
a = D("a")
f = E("f")
d = F("d")
b = G("b")
l = H("l")
n = I("n")
e = E("e")

c.s = n
c.v = n
c.o = h
c.w = f
c.t = e
j.t = b
j.r = b
h.z = j
a.p = j
a.q = b
f.z = j
f.s = e
f.o = h
d.x = a
d.t = e
d.p = e
d.q = n
d.s = c
d.w = l
b.o = a
l.y = d
l.s = c
l.u = b
l.t = j
n.o = j
n.s = a
n.t = a
n.p = l
e.z = j
e.s = f
e.o = h
assert d.s.s.p.s.txt == "c"