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

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

class C:
    def __init__(self, txt: str):
        self.s: C = None
        self.r: B = None
        self.o: G = None
        self.w: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: B = None
        self.r: D = None
        self.p: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: G = None
        self.s: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: E = None
        self.r: D = None
        self.q: G = None
        self.o: D = None
        self.p: A = None
        self.s: C = None
        self.txt = txt

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

j = A("j")
l = B("l")
c = C("c")
n = D("n")
e = E("e")
k = F("k")
h = G("h")
i = C("i")
f = D("f")
d = D("d")

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

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

class C:
    def __init__(self, txt: str):
        self.s: C = None
        self.r: B = None
        self.o: G = None
        self.w: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: B = None
        self.r: D = None
        self.p: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: G = None
        self.s: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: E = None
        self.r: D = None
        self.q: G = None
        self.o: D = None
        self.p: A = None
        self.s: C = None
        self.txt = txt

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

j = A("j")
l = B("l")
c = C("c")
n = D("n")
e = E("e")
k = F("k")
h = G("h")
i = C("i")
f = D("f")
d = D("d")

j.u = k
j.v = k
j.o = c
j.q = i
l.t = h
l.v = h
c.s = i
c.r = l
c.o = h
c.w = n
n.o = l
n.r = f
n.p = c
e.r = h
e.s = l
k.z = e
k.r = n
k.q = h
k.o = d
k.p = j
k.s = i
h.y = k
h.q = l
i.s = c
i.r = l
i.o = h
i.w = f
f.o = l
f.r = n
f.p = i
d.o = l
d.r = f
d.p = i
assert i.r.v.y.s.txt == "i"