class A:
    def __init__(self, txt: str):
        self.t: F = None
        self.z: B = None
        self.x: I = None
        self.y: I = None
        self.p: J = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.z: A = None
        self.u: A = None
        self.v: C = None
        self.x: H = None
        self.txt = txt

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

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

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

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

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

class J:
    def __init__(self, txt: str):
        self.o: D = None
        self.z: F = None
        self.q: E = None
        self.t: F = None
        self.txt = txt

f = A("f")
l = B("l")
k = C("k")
g = D("g")
n = E("n")
e = F("e")
h = G("h")
d = H("d")
i = I("i")
a = J("a")

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

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

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

class D:
    def __init__(self, txt: str):
        self.z: A = None
        self.u: A = None
        self.v: C = None
        self.x: H = None
        self.txt = txt

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

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

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

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

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

class J:
    def __init__(self, txt: str):
        self.o: D = None
        self.z: F = None
        self.q: E = None
        self.t: F = None
        self.txt = txt

f = A("f")
l = B("l")
k = C("k")
g = D("g")
n = E("n")
e = F("e")
h = G("h")
d = H("d")
i = I("i")
a = J("a")

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