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

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

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

class D:
    def __init__(self, txt: str):
        self.w: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: A = None
        self.w: H = None
        self.s: B = None
        self.o: A = None
        self.x: G = None
        self.v: C = None
        self.q: H = None
        self.y: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: H = None
        self.u: H = None
        self.r: B = None
        self.o: A = None
        self.y: E = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.u: F = None
        self.p: F = None
        self.v: H = None
        self.r: A = None
        self.z: D = None
        self.s: D = None
        self.txt = txt

k = A("k")
a = B("a")
m = C("m")
f = D("f")
c = E("c")
d = F("d")
n = G("n")
l = H("l")
j = I("j")

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

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

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

class D:
    def __init__(self, txt: str):
        self.w: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.u: A = None
        self.w: H = None
        self.s: B = None
        self.o: A = None
        self.x: G = None
        self.v: C = None
        self.q: H = None
        self.y: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: H = None
        self.u: H = None
        self.r: B = None
        self.o: A = None
        self.y: E = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.u: F = None
        self.p: F = None
        self.v: H = None
        self.r: A = None
        self.z: D = None
        self.s: D = None
        self.txt = txt

k = A("k")
a = B("a")
m = C("m")
f = D("f")
c = E("c")
d = F("d")
n = G("n")
l = H("l")
j = I("j")

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