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

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

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

class D:
    def __init__(self, txt: str):
        self.v: A = None
        self.x: B = None
        self.y: C = None
        self.r: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: G = None
        self.u: C = None
        self.y: D = None
        self.o: G = None
        self.v: C = None
        self.p: D = None
        self.w: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.v: B = None
        self.y: C = None
        self.t: A = None
        self.u: A = None
        self.s: B = None
        self.q: C = None
        self.x: B = None
        self.txt = txt

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.v: A = None
        self.x: B = None
        self.y: C = None
        self.r: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.s: G = None
        self.u: C = None
        self.y: D = None
        self.o: G = None
        self.v: C = None
        self.p: D = None
        self.w: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.v: B = None
        self.y: C = None
        self.t: A = None
        self.u: A = None
        self.s: B = None
        self.q: C = None
        self.x: B = None
        self.txt = txt

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

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