class A:
    def __init__(self, txt: str):
        self.u: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.p: E = None
        self.u: F = None
        self.x: G = None
        self.z: E = None
        self.o: E = None
        self.q: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.t: G = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.s: B = None
        self.u: H = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.v: F = None
        self.s: C = None
        self.y: C = None
        self.x: D = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.p: E = None
        self.u: F = None
        self.x: G = None
        self.z: E = None
        self.o: E = None
        self.q: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.t: G = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.s: B = None
        self.u: H = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.v: F = None
        self.s: C = None
        self.y: C = None
        self.x: D = None
        self.txt = txt

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

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

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