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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.y: B = None
        self.z: C = None
        self.s: C = None
        self.t: E = None
        self.u: E = None
        self.w: B = None
        self.txt = txt

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

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.y: B = None
        self.z: C = None
        self.s: C = None
        self.t: E = None
        self.u: E = None
        self.w: B = None
        self.txt = txt

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

d.x = c
d.t = k
d.z = e
d.o = l
d.y = i
e.u = c
e.z = c
c.v = l
c.z = e
c.y = e
c.o = j
j.r = c
j.w = c
j.q = d
j.t = k
j.v = m
j.s = m
i.z = d
i.o = e
i.t = e
k.y = e
k.w = e
k.z = c
k.s = c
k.t = i
k.u = i
l.x = c
l.t = m
l.z = e
l.o = d
l.y = i
m.y = e
m.w = e
m.z = c
m.s = c
m.t = i
m.u = i
assert d.z.z.y.u.o.v.t.z.txt == "d"