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

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

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

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

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

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

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

class H:
    def __init__(self, txt: str):
        self.o: I = None
        self.v: F = None
        self.q: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: C = None
        self.t: C = None
        self.o: D = None
        self.y: E = None
        self.v: H = None
        self.txt = txt

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

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

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

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

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

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

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

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

class H:
    def __init__(self, txt: str):
        self.o: I = None
        self.v: F = None
        self.q: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.u: C = None
        self.t: C = None
        self.o: D = None
        self.y: E = None
        self.v: H = None
        self.txt = txt

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

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