class A:
    def __init__(self, txt: str):
        self.x: E = None
        self.w: F = None
        self.p: E = None
        self.t: A = None
        self.o: D = None
        self.s: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.r: F = None
        self.w: F = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.r: F = None
        self.w: F = None
        self.txt = txt

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

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

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

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

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