class A:
    def __init__(self, txt: str):
        self.v: I = None
        self.z: B = None
        self.p: E = None
        self.w: B = None
        self.y: E = None
        self.t: B = None
        self.r: H = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.x: H = None
        self.v: H = None
        self.s: D = None
        self.r: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.r: F = None
        self.q: B = None
        self.p: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: H = None
        self.r: C = None
        self.x: G = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.x: H = None
        self.v: H = None
        self.s: D = None
        self.r: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.r: F = None
        self.q: B = None
        self.p: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: H = None
        self.r: C = None
        self.x: G = None
        self.txt = txt

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

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

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

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

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