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

class B:
    def __init__(self, txt: str):
        self.x: B = None
        self.q: F = None
        self.s: A = None
        self.o: E = None
        self.t: D = None
        self.r: E = None
        self.txt = txt

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

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.x: B = None
        self.q: F = None
        self.s: A = None
        self.o: E = None
        self.t: D = None
        self.r: E = None
        self.txt = txt

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

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

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

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

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

c.u = n
c.s = j
c.y = j
g.x = k
g.q = n
g.s = c
g.o = e
g.r = e
g.t = j
d.x = n
j.u = c
e.o = j
n.x = j
n.p = j
n.v = j
n.o = k
n.t = i
n.z = e
k.x = g
k.q = n
k.s = c
k.o = e
k.r = e
k.t = j
i.x = n
assert c.u.z.o.u.s.txt == "j"