class A:
    def __init__(self, txt: str):
        self.o: F = None
        self.txt = txt

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

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

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

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

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

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

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

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

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

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

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

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

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

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