class A:
    def __init__(self, txt: str):
        self.s: D = None
        self.v: F = None
        self.t: E = None
        self.x: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: D = None
        self.s: D = None
        self.w: D = None
        self.u: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: B = None
        self.x: E = None
        self.w: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: G = None
        self.y: C = None
        self.t: B = None
        self.z: G = None
        self.s: C = None
        self.txt = txt

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

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

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

n = A("n")
b = B("b")
m = C("m")
j = D("j")
l = E("l")
f = F("f")
h = G("h")
k = F("k")
i = G("i")

n.s = j
n.v = f
n.x = f
n.t = l
b.t = j
b.p = j
b.s = j
b.w = j
b.u = n
m.v = l
m.x = l
m.u = b
m.w = b
j.x = i
j.z = i
j.y = m
j.s = m
j.t = b
l.v = h
f.o = m
f.y = k
h.z = l
h.o = b
h.q = j
k.o = m
k.y = f
i.z = l
i.o = b
i.q = j
assert f.y.o.w.s.s.u.s.txt == "
class A:
    def __init__(self, txt: str):
        self.s: D = None
        self.v: F = None
        self.t: E = None
        self.x: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: D = None
        self.s: D = None
        self.w: D = None
        self.u: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: B = None
        self.x: E = None
        self.w: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: G = None
        self.y: C = None
        self.t: B = None
        self.z: G = None
        self.s: C = None
        self.txt = txt

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

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

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

n = A("n")
b = B("b")
m = C("m")
j = D("j")
l = E("l")
f = F("f")
h = G("h")
k = F("k")
i = G("i")

n.s = j
n.v = f
n.x = f
n.t = l
b.t = j
b.p = j
b.s = j
b.w = j
b.u = n
m.v = l
m.x = l
m.u = b
m.w = b
j.x = i
j.z = i
j.y = m
j.s = m
j.t = b
l.v = h
f.o = m
f.y = k
h.z = l
h.o = b
h.q = j
k.o = m
k.y = f
i.z = l
i.o = b
i.q = j
assert f.y.o.w.s.s.u.s.txt == "j"