class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.r: B = None
        self.y: F = None
        self.s: D = None
        self.x: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.o: D = None
        self.u: E = None
        self.x: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: F = None
        self.r: A = None
        self.t: E = None
        self.y: F = None
        self.z: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.y: B = None
        self.txt = txt

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.o: D = None
        self.u: E = None
        self.x: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.x: F = None
        self.r: A = None
        self.t: E = None
        self.y: F = None
        self.z: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.y: B = None
        self.txt = txt

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

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

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

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