class A:
    def __init__(self, txt: str):
        self.w: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.p: I = None
        self.q: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.s: F = None
        self.t: B = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.y: I = None
        self.p: A = None
        self.u: I = None
        self.o: D = None
        self.z: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: B = None
        self.s: C = None
        self.w: H = None
        self.u: I = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: D = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.p: I = None
        self.q: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.s: F = None
        self.t: B = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.y: I = None
        self.p: A = None
        self.u: I = None
        self.o: D = None
        self.z: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: B = None
        self.s: C = None
        self.w: H = None
        self.u: I = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: D = None
        self.txt = txt

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

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