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

class B:
    def __init__(self, txt: str):
        self.t: B = None
        self.p: G = None
        self.r: G = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: I = None
        self.r: D = None
        self.x: B = None
        self.s: H = None
        self.z: H = None
        self.y: C = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.u: G = None
        self.r: B = None
        self.p: B = None
        self.v: G = None
        self.t: G = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.t: B = None
        self.p: G = None
        self.r: G = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: I = None
        self.r: D = None
        self.x: B = None
        self.s: H = None
        self.z: H = None
        self.y: C = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.u: G = None
        self.r: B = None
        self.p: B = None
        self.v: G = None
        self.t: G = None
        self.txt = txt

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

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

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