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

class B:
    def __init__(self, txt: str):
        self.y: H = None
        self.z: D = None
        self.u: B = None
        self.r: H = None
        self.o: D = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.t: G = None
        self.p: C = None
        self.x: C = None
        self.s: H = None
        self.o: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: B = None
        self.t: H = None
        self.u: H = None
        self.x: A = None
        self.q: A = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: F = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: E = None
        self.u: E = None
        self.v: G = None
        self.x: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.y: H = None
        self.z: D = None
        self.u: B = None
        self.r: H = None
        self.o: D = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.t: G = None
        self.p: C = None
        self.x: C = None
        self.s: H = None
        self.o: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: B = None
        self.t: H = None
        self.u: H = None
        self.x: A = None
        self.q: A = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: F = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: E = None
        self.u: E = None
        self.v: G = None
        self.x: B = None
        self.txt = txt

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

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