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

class B:
    def __init__(self, txt: str):
        self.s: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.q: B = None
        self.r: H = None
        self.z: D = None
        self.u: B = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: B = None
        self.p: A = None
        self.o: F = None
        self.t: F = None
        self.r: F = None
        self.v: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: H = None
        self.s: B = None
        self.z: G = None
        self.txt = txt

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.s: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.q: B = None
        self.r: H = None
        self.z: D = None
        self.u: B = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: B = None
        self.p: A = None
        self.o: F = None
        self.t: F = None
        self.r: F = None
        self.v: C = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: H = None
        self.s: B = None
        self.z: G = None
        self.txt = txt

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

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

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

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

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