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

class B:
    def __init__(self, txt: str):
        self.y: G = None
        self.q: C = None
        self.w: D = None
        self.t: H = None
        self.u: I = None
        self.z: G = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.p: G = None
        self.y: F = None
        self.r: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: F = None
        self.v: H = None
        self.w: H = None
        self.r: D = None
        self.t: D = None
        self.u: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: E = None
        self.w: A = None
        self.t: G = None
        self.o: E = None
        self.x: H = None
        self.txt = txt

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.y: G = None
        self.q: C = None
        self.w: D = None
        self.t: H = None
        self.u: I = None
        self.z: G = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.p: G = None
        self.y: F = None
        self.r: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: F = None
        self.v: H = None
        self.w: H = None
        self.r: D = None
        self.t: D = None
        self.u: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: E = None
        self.w: A = None
        self.t: G = None
        self.o: E = None
        self.x: H = None
        self.txt = txt

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

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

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

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

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