class A:
    def __init__(self, txt: str):
        self.s: D = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.y: D = None
        self.z: A = None
        self.txt = txt

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

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.y: D = None
        self.z: A = None
        self.txt = txt

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

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

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