class A:
    def __init__(self, txt: str):
        self.o: F = None
        self.y: F = None
        self.v: J = None
        self.u: D = None
        self.w: J = None
        self.z: H = None
        self.t: E = None
        self.r: H = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.r: J = None
        self.y: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: A = None
        self.w: D = None
        self.o: B = None
        self.v: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.t: H = None
        self.r: J = None
        self.u: A = None
        self.p: I = None
        self.x: E = None
        self.v: A = None
        self.z: J = None
        self.s: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.v: I = None
        self.z: J = None
        self.p: B = None
        self.x: I = None
        self.o: J = None
        self.u: J = None
        self.s: B = None
        self.t: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.o: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.p: A = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.r: J = None
        self.y: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: A = None
        self.w: D = None
        self.o: B = None
        self.v: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.t: H = None
        self.r: J = None
        self.u: A = None
        self.p: I = None
        self.x: E = None
        self.v: A = None
        self.z: J = None
        self.s: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.v: I = None
        self.z: J = None
        self.p: B = None
        self.x: I = None
        self.o: J = None
        self.u: J = None
        self.s: B = None
        self.t: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.o: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.p: A = None
        self.txt = txt

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

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