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

class B:
    def __init__(self, txt: str):
        self.t: E = None
        self.s: D = None
        self.v: F = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.s: D = None
        self.z: D = None
        self.w: D = None
        self.txt = txt

a = A("a")
d = B("d")
e = C("e")
i = D("i")
g = E("g")
j = F("j")
l = D("l")
h = C("h")
c = A("c")
f = E("f")

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

class B:
    def __init__(self, txt: str):
        self.t: E = None
        self.s: D = None
        self.v: F = None
        self.txt = txt

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

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

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

class F:
    def __init__(self, txt: str):
        self.s: D = None
        self.z: D = None
        self.w: D = None
        self.txt = txt

a = A("a")
d = B("d")
e = C("e")
i = D("i")
g = E("g")
j = F("j")
l = D("l")
h = C("h")
c = A("c")
f = E("f")

a.v = l
d.t = f
d.s = i
d.v = j
e.u = a
e.q = a
e.t = j
e.r = h
e.p = g
e.y = c
i.p = a
i.z = a
i.o = d
i.y = d
i.v = d
i.r = h
g.s = a
g.w = a
j.s = i
j.z = i
j.w = l
l.p = a
l.z = a
l.o = d
l.y = d
l.v = d
l.r = e
h.u = c
h.q = c
h.y = c
h.t = j
h.r = e
h.p = f
c.v = l
f.s = c
f.w = a
assert e.r.p.w.v.y.s.r.y.txt == "c"