class A:
    def __init__(self, txt: str):
        self.s: I = None
        self.o: D = None
        self.z: E = None
        self.r: E = None
        self.txt = txt

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

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.t: A = None
        self.u: F = None
        self.p: H = None
        self.q: D = None
        self.r: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: D = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.s: H = None
        self.r: E = None
        self.v: H = None
        self.q: C = None
        self.txt = txt

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

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

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

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.t: A = None
        self.u: F = None
        self.p: H = None
        self.q: D = None
        self.r: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.x: D = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.s: H = None
        self.r: E = None
        self.v: H = None
        self.q: C = None
        self.txt = txt

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

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