class A:
    def __init__(self, txt: str):
        self.u: E = None
        self.z: G = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.x: E = None
        self.y: B = None
        self.v: I = None
        self.u: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: I = None
        self.q: A = None
        self.u: H = None
        self.r: A = None
        self.w: I = None
        self.v: B = None
        self.s: H = None
        self.p: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: E = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.x: E = None
        self.y: B = None
        self.v: I = None
        self.u: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.z: I = None
        self.q: A = None
        self.u: H = None
        self.r: A = None
        self.w: I = None
        self.v: B = None
        self.s: H = None
        self.p: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.z: E = None
        self.txt = txt

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

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

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