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

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

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

class D:
    def __init__(self, txt: str):
        self.t: A = None
        self.p: F = None
        self.z: C = None
        self.s: A = None
        self.o: H = None
        self.w: B = None
        self.x: C = None
        self.v: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.r: A = None
        self.o: B = None
        self.z: A = None
        self.v: E = None
        self.s: C = None
        self.w: E = None
        self.t: I = None
        self.txt = txt

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

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.t: A = None
        self.p: F = None
        self.z: C = None
        self.s: A = None
        self.o: H = None
        self.w: B = None
        self.x: C = None
        self.v: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.r: A = None
        self.o: B = None
        self.z: A = None
        self.v: E = None
        self.s: C = None
        self.w: E = None
        self.t: I = None
        self.txt = txt

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

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

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

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