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

class B:
    def __init__(self, txt: str):
        self.q: A = None
        self.y: I = None
        self.o: J = None
        self.s: F = None
        self.v: I = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.s: I = None
        self.q: F = None
        self.w: A = None
        self.u: J = None
        self.o: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: B = None
        self.q: I = None
        self.p: J = None
        self.s: I = None
        self.w: D = None
        self.o: H = None
        self.r: I = None
        self.v: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.p: E = None
        self.y: J = None
        self.q: H = None
        self.z: E = None
        self.t: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: D = None
        self.p: J = None
        self.q: A = None
        self.u: F = None
        self.o: J = None
        self.t: C = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: F = None
        self.z: C = None
        self.x: E = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.u: A = None
        self.t: I = None
        self.r: C = None
        self.z: H = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.q: A = None
        self.y: I = None
        self.o: J = None
        self.s: F = None
        self.v: I = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.s: I = None
        self.q: F = None
        self.w: A = None
        self.u: J = None
        self.o: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: B = None
        self.q: I = None
        self.p: J = None
        self.s: I = None
        self.w: D = None
        self.o: H = None
        self.r: I = None
        self.v: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.p: E = None
        self.y: J = None
        self.q: H = None
        self.z: E = None
        self.t: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.v: D = None
        self.p: J = None
        self.q: A = None
        self.u: F = None
        self.o: J = None
        self.t: C = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.y: C = None
        self.p: F = None
        self.z: C = None
        self.x: E = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.u: A = None
        self.t: I = None
        self.r: C = None
        self.z: H = None
        self.txt = txt

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

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