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

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

class C:
    def __init__(self, txt: str):
        self.t: E = None
        self.u: E = None
        self.r: D = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.t: E = None
        self.u: E = None
        self.r: D = None
        self.txt = txt

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

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

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

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

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