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

class B:
    def __init__(self, txt: str):
        self.v: E = None
        self.y: F = None
        self.u: A = None
        self.t: H = None
        self.z: I = None
        self.p: C = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.x: F = None
        self.y: G = None
        self.u: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: F = None
        self.q: B = None
        self.z: D = None
        self.o: H = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: E = None
        self.v: E = None
        self.q: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.x: E = None
        self.v: D = None
        self.u: H = None
        self.r: I = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.v: E = None
        self.y: F = None
        self.u: A = None
        self.t: H = None
        self.z: I = None
        self.p: C = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.x: F = None
        self.y: G = None
        self.u: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: F = None
        self.q: B = None
        self.z: D = None
        self.o: H = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: E = None
        self.v: E = None
        self.q: A = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.x: E = None
        self.v: D = None
        self.u: H = None
        self.r: I = None
        self.txt = txt

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

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