class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.x: H = None
        self.y: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.s: B = None
        self.v: G = None
        self.w: F = None
        self.r: B = None
        self.o: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: I = None
        self.w: A = None
        self.q: H = None
        self.v: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: I = None
        self.u: C = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: D = None
        self.s: B = None
        self.w: D = None
        self.v: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: G = None
        self.u: C = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.s: B = None
        self.v: G = None
        self.w: F = None
        self.r: B = None
        self.o: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: I = None
        self.w: A = None
        self.q: H = None
        self.v: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.r: I = None
        self.u: C = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: D = None
        self.s: B = None
        self.w: D = None
        self.v: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: G = None
        self.u: C = None
        self.txt = txt

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

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

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