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

class B:
    def __init__(self, txt: str):
        self.y: H = None
        self.u: F = None
        self.v: I = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.v: A = None
        self.z: I = None
        self.t: B = None
        self.q: H = None
        self.y: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.u: I = None
        self.q: B = None
        self.p: B = None
        self.x: C = None
        self.r: H = None
        self.y: E = None
        self.v: H = None
        self.s: C = None
        self.o: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: G = None
        self.o: C = None
        self.s: I = None
        self.x: I = None
        self.v: D = None
        self.t: B = None
        self.p: B = None
        self.w: C = None
        self.q: F = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.y: H = None
        self.u: F = None
        self.v: I = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.v: A = None
        self.z: I = None
        self.t: B = None
        self.q: H = None
        self.y: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.u: I = None
        self.q: B = None
        self.p: B = None
        self.x: C = None
        self.r: H = None
        self.y: E = None
        self.v: H = None
        self.s: C = None
        self.o: F = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: G = None
        self.o: C = None
        self.s: I = None
        self.x: I = None
        self.v: D = None
        self.t: B = None
        self.p: B = None
        self.w: C = None
        self.q: F = None
        self.txt = txt

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

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

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