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

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

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

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

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

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

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

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

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

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

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

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

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

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

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