class A:
    def __init__(self, txt: str):
        self.u: E = None
        self.x: D = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: I = None
        self.z: C = None
        self.w: D = None
        self.t: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.p: G = None
        self.s: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: B = None
        self.y: A = None
        self.z: E = None
        self.r: I = None
        self.u: A = None
        self.x: A = None
        self.s: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: C = None
        self.w: H = None
        self.r: A = None
        self.v: A = None
        self.t: D = None
        self.p: I = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: B = None
        self.w: F = None
        self.y: F = None
        self.t: C = None
        self.q: B = None
        self.u: E = None
        self.v: B = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.r: I = None
        self.z: C = None
        self.w: D = None
        self.t: A = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.v: D = None
        self.p: G = None
        self.s: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: B = None
        self.y: A = None
        self.z: E = None
        self.r: I = None
        self.u: A = None
        self.x: A = None
        self.s: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: C = None
        self.w: H = None
        self.r: A = None
        self.v: A = None
        self.t: D = None
        self.p: I = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: B = None
        self.w: F = None
        self.y: F = None
        self.t: C = None
        self.q: B = None
        self.u: E = None
        self.v: B = None
        self.txt = txt

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

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

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