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

class B:
    def __init__(self, txt: str):
        self.z: A = None
        self.txt = txt

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

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.z: A = None
        self.txt = txt

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

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

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

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

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

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