class A:
    def __init__(self, txt: str):
        self.w: I = None
        self.q: I = None
        self.v: B = None
        self.r: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.w: E = None
        self.z: E = None
        self.p: F = None
        self.v: I = None
        self.q: A = None
        self.x: A = None
        self.u: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.r: C = None
        self.v: B = None
        self.t: A = None
        self.y: F = None
        self.p: A = None
        self.s: F = None
        self.q: F = None
        self.w: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: G = None
        self.x: B = None
        self.o: G = None
        self.q: H = None
        self.s: B = None
        self.y: H = None
        self.r: A = None
        self.v: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: D = None
        self.v: A = None
        self.y: I = None
        self.p: H = None
        self.o: E = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.y: I = None
        self.u: D = None
        self.t: I = None
        self.q: D = None
        self.z: B = None
        self.r: C = None
        self.o: G = None
        self.s: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: F = None
        self.q: E = None
        self.txt = txt

b = A("b")
i = B("i")
l = C("l")
m = D("m")
h = E("h")
n = F("n")
a = G("a")
k = H("k")
f = I("f")
c = G("c")

b.w = f
b.q = f
b.v = i
b.r = i
i.w = h
i.z = h
i.u = h
i.p = n
i.v = f
i.q = b
i.x = b
l.p = c
l.z = b
l.s = b
l.r = n
m.r = l
m.v = i
m.t = b
m.p = b
m.y = n
m.s = n
m.q = n
m.w = f
h.p = c
h.o = c
h.x = i
h.s = i
h.q = k
h.y = k
h.r = b
h.v = a
n.z = m
n.v = b
n.y = f
n.p = k
n.o = h
a.w = c
k.y = f
k.t = f
k.u = m
k.q = m
k.z = i
k.r = l
k.o = c
k.s = h
f.p = n
f.q = h
c.w = a
assert l.r.v.v.p.y.txt == "
class A:
    def __init__(self, txt: str):
        self.w: I = None
        self.q: I = None
        self.v: B = None
        self.r: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.w: E = None
        self.z: E = None
        self.p: F = None
        self.v: I = None
        self.q: A = None
        self.x: A = None
        self.u: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.r: C = None
        self.v: B = None
        self.t: A = None
        self.y: F = None
        self.p: A = None
        self.s: F = None
        self.q: F = None
        self.w: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: G = None
        self.x: B = None
        self.o: G = None
        self.q: H = None
        self.s: B = None
        self.y: H = None
        self.r: A = None
        self.v: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: D = None
        self.v: A = None
        self.y: I = None
        self.p: H = None
        self.o: E = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.y: I = None
        self.u: D = None
        self.t: I = None
        self.q: D = None
        self.z: B = None
        self.r: C = None
        self.o: G = None
        self.s: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: F = None
        self.q: E = None
        self.txt = txt

b = A("b")
i = B("i")
l = C("l")
m = D("m")
h = E("h")
n = F("n")
a = G("a")
k = H("k")
f = I("f")
c = G("c")

b.w = f
b.q = f
b.v = i
b.r = i
i.w = h
i.z = h
i.u = h
i.p = n
i.v = f
i.q = b
i.x = b
l.p = c
l.z = b
l.s = b
l.r = n
m.r = l
m.v = i
m.t = b
m.p = b
m.y = n
m.s = n
m.q = n
m.w = f
h.p = c
h.o = c
h.x = i
h.s = i
h.q = k
h.y = k
h.r = b
h.v = a
n.z = m
n.v = b
n.y = f
n.p = k
n.o = h
a.w = c
k.y = f
k.t = f
k.u = m
k.q = m
k.z = i
k.r = l
k.o = c
k.s = h
f.p = n
f.q = h
c.w = a
assert l.r.v.v.p.y.txt == "f"