class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.y: C = None
        self.q: E = None
        self.o: F = None
        self.x: C = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.q: C = None
        self.t: A = None
        self.y: F = None
        self.p: C = None
        self.s: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: C = None
        self.z: A = None
        self.x: B = None
        self.o: C = None
        self.q: D = None
        self.txt = txt

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

e.v = d
e.o = d
e.y = i
e.x = i
e.q = f
j.z = i
j.x = m
j.y = g
i.x = f
i.z = f
i.w = g
i.s = m
i.p = m
i.v = d
m.q = i
m.p = i
m.t = e
m.y = d
m.s = d
f.v = a
d.w = i
d.t = i
d.o = i
d.z = e
d.x = a
d.q = m
a.z = i
a.x = l
a.y = f
c.z = i
c.x = l
c.y = g
g.v = a
l.q = i
l.p = i
l.t = e
l.y = d
l.s = d
assert f.v.y.v.z.z.v.y.v.txt == "
class A:
    def __init__(self, txt: str):
        self.v: F = None
        self.y: C = None
        self.q: E = None
        self.o: F = None
        self.x: C = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.q: C = None
        self.t: A = None
        self.y: F = None
        self.p: C = None
        self.s: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.w: C = None
        self.t: C = None
        self.z: A = None
        self.x: B = None
        self.o: C = None
        self.q: D = None
        self.txt = txt

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

e.v = d
e.o = d
e.y = i
e.x = i
e.q = f
j.z = i
j.x = m
j.y = g
i.x = f
i.z = f
i.w = g
i.s = m
i.p = m
i.v = d
m.q = i
m.p = i
m.t = e
m.y = d
m.s = d
f.v = a
d.w = i
d.t = i
d.o = i
d.z = e
d.x = a
d.q = m
a.z = i
a.x = l
a.y = f
c.z = i
c.x = l
c.y = g
g.v = a
l.q = i
l.p = i
l.t = e
l.y = d
l.s = d
assert f.v.y.v.z.z.v.y.v.txt == "a"