class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.t: F = None
        self.o: F = None
        self.x: F = None
        self.z: F = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.q: B = None
        self.y: B = None
        self.s: A = None
        self.v: D = None
        self.w: B = None
        self.p: B = None
        self.u: B = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.p: E = None
        self.y: A = None
        self.q: E = None
        self.u: C = None
        self.r: E = None
        self.v: C = None
        self.o: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: A = None
        self.w: F = None
        self.txt = txt

j = A("j")
k = B("k")
f = C("f")
i = D("i")
h = E("h")
a = F("a")
l = G("l")
b = F("b")
c = D("c")

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

class B:
    def __init__(self, txt: str):
        self.t: F = None
        self.o: F = None
        self.x: F = None
        self.z: F = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.q: B = None
        self.y: B = None
        self.s: A = None
        self.v: D = None
        self.w: B = None
        self.p: B = None
        self.u: B = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.p: E = None
        self.y: A = None
        self.q: E = None
        self.u: C = None
        self.r: E = None
        self.v: C = None
        self.o: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: A = None
        self.w: F = None
        self.txt = txt

j = A("j")
k = B("k")
f = C("f")
i = D("i")
h = E("h")
a = F("a")
l = G("l")
b = F("b")
c = D("c")

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