class A:
    def __init__(self, txt: str):
        self.z: C = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.y: D = None
        self.x: B = None
        self.u: D = None
        self.r: B = None
        self.o: E = None
        self.txt = txt

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

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

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

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.y: D = None
        self.x: B = None
        self.u: D = None
        self.r: B = None
        self.o: E = None
        self.txt = txt

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

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

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

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

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