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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.t: I = None
        self.u: C = None
        self.p: A = None
        self.z: H = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.w: F = None
        self.z: F = None
        self.r: C = None
        self.y: D = None
        self.t: A = None
        self.p: F = None
        self.txt = txt

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

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

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.t: I = None
        self.u: C = None
        self.p: A = None
        self.z: H = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.w: F = None
        self.z: F = None
        self.r: C = None
        self.y: D = None
        self.t: A = None
        self.p: F = None
        self.txt = txt

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

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

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