class A:
    def __init__(self, txt: str):
        self.w: F = None
        self.u: H = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.t: I = None
        self.y: A = None
        self.r: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: I = None
        self.y: E = None
        self.u: B = None
        self.r: I = None
        self.t: D = None
        self.v: G = None
        self.w: F = None
        self.txt = txt

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

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

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

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

class H:
    def __init__(self, txt: str):
        self.u: B = None
        self.y: D = None
        self.q: E = None
        self.v: C = None
        self.w: F = None
        self.o: E = None
        self.s: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.s: G = None
        self.z: I = None
        self.txt = txt

f = A("f")
d = B("d")
b = C("b")
i = D("i")
e = E("e")
h = F("h")
l = G("l")
m = H("m")
j = I("j")
k = I("k")

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

class B:
    def __init__(self, txt: str):
        self.t: I = None
        self.y: A = None
        self.r: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: I = None
        self.y: E = None
        self.u: B = None
        self.r: I = None
        self.t: D = None
        self.v: G = None
        self.w: F = None
        self.txt = txt

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

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

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

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

class H:
    def __init__(self, txt: str):
        self.u: B = None
        self.y: D = None
        self.q: E = None
        self.v: C = None
        self.w: F = None
        self.o: E = None
        self.s: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.s: G = None
        self.z: I = None
        self.txt = txt

f = A("f")
d = B("d")
b = C("b")
i = D("i")
e = E("e")
h = F("h")
l = G("l")
m = H("m")
j = I("j")
k = I("k")

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