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

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

class C:
    def __init__(self, txt: str):
        self.x: E = None
        self.y: B = None
        self.o: G = None
        self.z: F = None
        self.p: F = None
        self.v: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: C = None
        self.q: F = None
        self.o: D = None
        self.w: D = None
        self.z: B = None
        self.s: B = None
        self.y: C = None
        self.p: A = None
        self.v: F = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.z: C = None
        self.t: F = None
        self.u: A = None
        self.s: E = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.x: E = None
        self.y: B = None
        self.o: G = None
        self.z: F = None
        self.p: F = None
        self.v: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: C = None
        self.q: F = None
        self.o: D = None
        self.w: D = None
        self.z: B = None
        self.s: B = None
        self.y: C = None
        self.p: A = None
        self.v: F = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.z: C = None
        self.t: F = None
        self.u: A = None
        self.s: E = None
        self.txt = txt

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

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