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

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

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

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

class E:
    def __init__(self, txt: str):
        self.y: H = None
        self.r: G = None
        self.z: C = None
        self.o: J = None
        self.s: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: H = None
        self.y: A = None
        self.w: B = None
        self.v: H = None
        self.z: J = None
        self.r: D = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.u: I = None
        self.o: J = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: J = None
        self.t: B = None
        self.o: F = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.t: I = None
        self.w: I = None
        self.u: G = None
        self.q: D = None
        self.z: H = None
        self.x: I = None
        self.v: C = None
        self.o: H = None
        self.txt = txt

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.y: H = None
        self.r: G = None
        self.z: C = None
        self.o: J = None
        self.s: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.o: H = None
        self.y: A = None
        self.w: B = None
        self.v: H = None
        self.z: J = None
        self.r: D = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.u: I = None
        self.o: J = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: J = None
        self.t: B = None
        self.o: F = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.t: I = None
        self.w: I = None
        self.u: G = None
        self.q: D = None
        self.z: H = None
        self.x: I = None
        self.v: C = None
        self.o: H = None
        self.txt = txt

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

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