class A:
    def __init__(self, txt: str):
        self.o: D = None
        self.s: F = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.y: B = None
        self.w: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: C = None
        self.y: G = None
        self.o: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.w: C = None
        self.x: F = None
        self.t: C = None
        self.s: E = None
        self.q: H = None
        self.o: B = None
        self.z: C = None
        self.p: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.y: A = None
        self.u: E = None
        self.txt = txt

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.y: B = None
        self.w: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: C = None
        self.y: G = None
        self.o: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.w: C = None
        self.x: F = None
        self.t: C = None
        self.s: E = None
        self.q: H = None
        self.o: B = None
        self.z: C = None
        self.p: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.y: A = None
        self.u: E = None
        self.txt = txt

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

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