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

class B:
    def __init__(self, txt: str):
        self.z: H = None
        self.s: A = None
        self.q: H = None
        self.r: I = None
        self.u: H = None
        self.p: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: A = None
        self.p: D = None
        self.q: A = None
        self.x: F = None
        self.v: D = None
        self.s: A = None
        self.o: G = None
        self.t: F = None
        self.y: G = None
        self.z: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: J = None
        self.r: A = None
        self.u: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.q: I = None
        self.y: H = None
        self.o: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.t: A = None
        self.q: C = None
        self.r: D = None
        self.y: H = None
        self.s: F = None
        self.w: I = None
        self.z: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.r: D = None
        self.o: D = None
        self.p: D = None
        self.y: I = None
        self.z: J = None
        self.q: E = None
        self.u: G = None
        self.w: G = None
        self.txt = txt

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.z: H = None
        self.s: A = None
        self.q: H = None
        self.r: I = None
        self.u: H = None
        self.p: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: A = None
        self.p: D = None
        self.q: A = None
        self.x: F = None
        self.v: D = None
        self.s: A = None
        self.o: G = None
        self.t: F = None
        self.y: G = None
        self.z: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: J = None
        self.r: A = None
        self.u: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.q: I = None
        self.y: H = None
        self.o: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.t: A = None
        self.q: C = None
        self.r: D = None
        self.y: H = None
        self.s: F = None
        self.w: I = None
        self.z: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.r: D = None
        self.o: D = None
        self.p: D = None
        self.y: I = None
        self.z: J = None
        self.q: E = None
        self.u: G = None
        self.w: G = None
        self.txt = txt

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

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

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

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