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

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

class C:
    def __init__(self, txt: str):
        self.o: F = None
        self.t: F = None
        self.u: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.x: C = None
        self.o: A = None
        self.t: C = None
        self.y: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: D = None
        self.p: A = None
        self.o: B = None
        self.t: F = None
        self.u: F = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.o: F = None
        self.t: F = None
        self.u: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.x: C = None
        self.o: A = None
        self.t: C = None
        self.y: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: D = None
        self.p: A = None
        self.o: B = None
        self.t: F = None
        self.u: F = None
        self.txt = txt

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

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