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

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.v: D = None
        self.z: F = None
        self.x: G = None
        self.p: A = None
        self.y: D = None
        self.s: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: H = None
        self.y: G = None
        self.q: I = None
        self.t: I = None
        self.o: H = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.u: B = None
        self.x: G = None
        self.s: E = None
        self.z: F = None
        self.p: E = None
        self.w: H = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.v: D = None
        self.z: F = None
        self.x: G = None
        self.p: A = None
        self.y: D = None
        self.s: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.x: H = None
        self.y: G = None
        self.q: I = None
        self.t: I = None
        self.o: H = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.u: B = None
        self.x: G = None
        self.s: E = None
        self.z: F = None
        self.p: E = None
        self.w: H = None
        self.txt = txt

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

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