class A:
    def __init__(self, txt: str):
        self.y: I = None
        self.t: H = None
        self.p: C = None
        self.u: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: F = None
        self.z: H = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.x: F = None
        self.r: C = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: C = None
        self.v: C = None
        self.z: F = None
        self.q: C = None
        self.w: I = None
        self.r: D = None
        self.x: I = None
        self.o: D = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: G = None
        self.u: E = None
        self.y: A = None
        self.x: E = None
        self.o: G = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.r: F = None
        self.z: H = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.s: E = None
        self.x: F = None
        self.r: C = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: C = None
        self.v: C = None
        self.z: F = None
        self.q: C = None
        self.w: I = None
        self.r: D = None
        self.x: I = None
        self.o: D = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: G = None
        self.u: E = None
        self.y: A = None
        self.x: E = None
        self.o: G = None
        self.txt = txt

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

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

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