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

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.y: I = None
        self.x: D = None
        self.z: C = None
        self.t: A = None
        self.o: F = None
        self.p: I = None
        self.r: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: I = None
        self.v: I = None
        self.w: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.u: C = None
        self.r: C = None
        self.p: C = None
        self.x: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: B = None
        self.x: H = None
        self.u: I = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.y: E = None
        self.s: G = None
        self.t: F = None
        self.p: G = None
        self.o: H = None
        self.w: F = None
        self.r: E = None
        self.txt = txt

c = A("c")
m = B("m")
e = C("e")
a = D("a")
f = E("f")
h = F("h")
k = G("k")
i = H("i")
b = I("b")

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

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.y: I = None
        self.x: D = None
        self.z: C = None
        self.t: A = None
        self.o: F = None
        self.p: I = None
        self.r: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: I = None
        self.v: I = None
        self.w: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.u: C = None
        self.r: C = None
        self.p: C = None
        self.x: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: B = None
        self.x: H = None
        self.u: I = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.y: E = None
        self.s: G = None
        self.t: F = None
        self.p: G = None
        self.o: H = None
        self.w: F = None
        self.r: E = None
        self.txt = txt

c = A("c")
m = B("m")
e = C("e")
a = D("a")
f = E("f")
h = F("h")
k = G("k")
i = H("i")
b = I("b")

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