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

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

class C:
    def __init__(self, txt: str):
        self.o: F = None
        self.x: E = None
        self.s: E = None
        self.w: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: D = None
        self.r: G = None
        self.s: I = None
        self.v: A = None
        self.x: F = None
        self.q: B = None
        self.w: A = None
        self.t: A = None
        self.u: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.t: E = None
        self.r: E = None
        self.w: G = None
        self.u: E = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.o: F = None
        self.x: E = None
        self.s: E = None
        self.w: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: D = None
        self.r: G = None
        self.s: I = None
        self.v: A = None
        self.x: F = None
        self.q: B = None
        self.w: A = None
        self.t: A = None
        self.u: D = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.t: E = None
        self.r: E = None
        self.w: G = None
        self.u: E = None
        self.txt = txt

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

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

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