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

class B:
    def __init__(self, txt: str):
        self.w: E = None
        self.x: D = None
        self.s: E = None
        self.p: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: D = None
        self.x: A = None
        self.w: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.r: B = None
        self.x: D = None
        self.y: A = None
        self.q: D = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: C = None
        self.q: B = None
        self.s: F = None
        self.w: D = None
        self.u: B = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.w: E = None
        self.x: D = None
        self.s: E = None
        self.p: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.u: D = None
        self.x: A = None
        self.w: C = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.r: B = None
        self.x: D = None
        self.y: A = None
        self.q: D = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: C = None
        self.q: B = None
        self.s: F = None
        self.w: D = None
        self.u: B = None
        self.txt = txt

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

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

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