class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.u: I = None
        self.w: F = None
        self.z: G = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.o: B = None
        self.v: H = None
        self.z: I = None
        self.u: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.y: A = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.s: C = None
        self.o: F = None
        self.z: B = None
        self.x: H = None
        self.t: C = None
        self.v: C = None
        self.w: E = None
        self.txt = txt

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

j.v = d
j.w = d
j.u = e
j.z = a
k.p = n
k.z = b
k.y = i
k.v = i
i.s = n
i.r = d
n.o = k
n.v = b
n.z = e
n.u = l
m.x = b
d.x = j
d.p = i
a.y = j
b.x = a
b.r = a
b.u = a
b.v = e
b.o = k
b.t = k
b.s = k
b.y = i
e.s = i
e.t = i
e.v = i
e.o = d
e.z = k
e.x = b
e.w = l
l.x = b
assert n.u.x.v.w.x.s.y.s.txt == "
class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.u: I = None
        self.w: F = None
        self.z: G = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.o: B = None
        self.v: H = None
        self.z: I = None
        self.u: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.y: A = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.s: C = None
        self.o: F = None
        self.z: B = None
        self.x: H = None
        self.t: C = None
        self.v: C = None
        self.w: E = None
        self.txt = txt

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

j.v = d
j.w = d
j.u = e
j.z = a
k.p = n
k.z = b
k.y = i
k.v = i
i.s = n
i.r = d
n.o = k
n.v = b
n.z = e
n.u = l
m.x = b
d.x = j
d.p = i
a.y = j
b.x = a
b.r = a
b.u = a
b.v = e
b.o = k
b.t = k
b.s = k
b.y = i
e.s = i
e.t = i
e.v = i
e.o = d
e.z = k
e.x = b
e.w = l
l.x = b
assert n.u.x.v.w.x.s.y.s.txt == "n"