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

class B:
    def __init__(self, txt: str):
        self.u: F = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.o: J = None
        self.r: C = None
        self.p: I = None
        self.q: G = None
        self.y: E = None
        self.s: C = None
        self.x: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.u: J = None
        self.x: C = None
        self.txt = txt

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

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

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

class J:
    def __init__(self, txt: str):
        self.v: F = None
        self.z: C = None
        self.s: F = None
        self.o: I = None
        self.t: C = None
        self.q: F = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.u: F = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.o: J = None
        self.r: C = None
        self.p: I = None
        self.q: G = None
        self.y: E = None
        self.s: C = None
        self.x: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.u: J = None
        self.x: C = None
        self.txt = txt

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

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

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

class J:
    def __init__(self, txt: str):
        self.v: F = None
        self.z: C = None
        self.s: F = None
        self.o: I = None
        self.t: C = None
        self.q: F = None
        self.txt = txt

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

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