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

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.s: A = None
        self.v: H = None
        self.y: D = None
        self.r: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: E = None
        self.w: A = None
        self.q: G = None
        self.p: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: A = None
        self.t: H = None
        self.y: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.q: G = None
        self.w: H = None
        self.x: G = None
        self.r: D = None
        self.y: C = None
        self.s: D = None
        self.u: A = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.o: D = None
        self.u: D = None
        self.t: E = None
        self.txt = txt

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.q: D = None
        self.s: A = None
        self.v: H = None
        self.y: D = None
        self.r: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.y: E = None
        self.w: A = None
        self.q: G = None
        self.p: F = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: A = None
        self.t: H = None
        self.y: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.q: G = None
        self.w: H = None
        self.x: G = None
        self.r: D = None
        self.y: C = None
        self.s: D = None
        self.u: A = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.o: D = None
        self.u: D = None
        self.t: E = None
        self.txt = txt

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

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

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

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