class A:
    def __init__(self, txt: str):
        self.v: D = None
        self.p: E = None
        self.r: C = None
        self.q: B = None
        self.z: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.p: D = None
        self.o: E = None
        self.t: F = None
        self.q: G = None
        self.r: D = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.t: B = None
        self.s: E = None
        self.u: G = None
        self.o: A = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.p: D = None
        self.o: E = None
        self.t: F = None
        self.q: G = None
        self.r: D = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.t: B = None
        self.s: E = None
        self.u: G = None
        self.o: A = None
        self.txt = txt

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

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

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