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

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

class C:
    def __init__(self, txt: str):
        self.s: F = None
        self.w: D = None
        self.z: G = None
        self.u: B = None
        self.t: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: H = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.y: H = None
        self.x: H = None
        self.r: C = None
        self.t: I = None
        self.s: F = None
        self.p: E = None
        self.v: E = None
        self.txt = txt

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.s: F = None
        self.w: D = None
        self.z: G = None
        self.u: B = None
        self.t: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: H = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.y: H = None
        self.x: H = None
        self.r: C = None
        self.t: I = None
        self.s: F = None
        self.p: E = None
        self.v: E = None
        self.txt = txt

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

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

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

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