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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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