class A:
    def __init__(self, txt: str):
        self.s: A = None
        self.q: F = None
        self.o: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.z: C = None
        self.p: F = None
        self.o: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.t: B = None
        self.x: B = None
        self.w: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.s: C = None
        self.u: A = None
        self.y: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: C = None
        self.u: C = None
        self.x: E = None
        self.y: D = None
        self.t: F = None
        self.v: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.z: C = None
        self.p: F = None
        self.o: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.t: B = None
        self.x: B = None
        self.w: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.s: C = None
        self.u: A = None
        self.y: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: C = None
        self.u: C = None
        self.x: E = None
        self.y: D = None
        self.t: F = None
        self.v: B = None
        self.txt = txt

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

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