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

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.s: A = None
        self.q: G = None
        self.z: I = None
        self.v: I = None
        self.w: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: D = None
        self.z: A = None
        self.v: B = None
        self.x: I = None
        self.q: F = None
        self.w: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: F = None
        self.w: D = None
        self.r: A = None
        self.q: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: I = None
        self.t: B = None
        self.s: B = None
        self.z: D = None
        self.o: I = None
        self.w: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: D = None
        self.q: E = None
        self.z: E = None
        self.u: H = None
        self.o: F = None
        self.r: F = None
        self.y: H = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.x: A = None
        self.s: A = None
        self.q: G = None
        self.z: I = None
        self.v: I = None
        self.w: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: D = None
        self.z: A = None
        self.v: B = None
        self.x: I = None
        self.q: F = None
        self.w: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.s: F = None
        self.w: D = None
        self.r: A = None
        self.q: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: I = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: I = None
        self.t: B = None
        self.s: B = None
        self.z: D = None
        self.o: I = None
        self.w: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: D = None
        self.q: E = None
        self.z: E = None
        self.u: H = None
        self.o: F = None
        self.r: F = None
        self.y: H = None
        self.txt = txt

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

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