class A:
    def __init__(self, txt: str):
        self.u: G = None
        self.v: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: D = None
        self.y: A = None
        self.txt = txt

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

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

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

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

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

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

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

j.u = d
j.v = n
f.r = e
e.w = h
e.y = j
h.y = e
n.z = e
b.t = e
b.z = f
d.o = n
d.z = h
d.p = h
d.q = h
d.t = f
d.s = g
d.v = e
d.x = k
d.u = i
i.x = d
i.q = b
i.z = e
i.o = e
i.r = k
i.v = h
i.s = h
i.w = n
g.v = f
g.p = d
g.z = h
g.u = n
k.u = d
k.v = n
assert h.y.w.y.txt == "
class A:
    def __init__(self, txt: str):
        self.u: G = None
        self.v: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: D = None
        self.y: A = None
        self.txt = txt

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

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

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

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

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

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

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

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