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

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

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

class D:
    def __init__(self, txt: str):
        self.s: I = None
        self.t: A = None
        self.x: I = None
        self.o: I = None
        self.p: E = None
        self.v: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: C = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.w: A = None
        self.o: E = None
        self.r: E = None
        self.y: A = None
        self.x: B = None
        self.z: E = None
        self.v: B = None
        self.u: F = None
        self.txt = txt

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.s: I = None
        self.t: A = None
        self.x: I = None
        self.o: I = None
        self.p: E = None
        self.v: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: C = None
        self.txt = txt

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

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

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

class I:
    def __init__(self, txt: str):
        self.w: A = None
        self.o: E = None
        self.r: E = None
        self.y: A = None
        self.x: B = None
        self.z: E = None
        self.v: B = None
        self.u: F = None
        self.txt = txt

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

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