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

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

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

class D:
    def __init__(self, txt: str):
        self.u: F = None
        self.w: C = None
        self.y: B = None
        self.s: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.z: D = None
        self.w: F = None
        self.p: B = None
        self.s: D = None
        self.x: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.w: C = None
        self.txt = txt

n = A("n")
a = B("a")
f = C("f")
h = D("h")
j = E("j")
e = F("e")
k = B("k")
g = F("g")
i = B("i")
b = B("b")

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

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

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

class D:
    def __init__(self, txt: str):
        self.u: F = None
        self.w: C = None
        self.y: B = None
        self.s: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.z: D = None
        self.w: F = None
        self.p: B = None
        self.s: D = None
        self.x: B = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.w: C = None
        self.txt = txt

n = A("n")
a = B("a")
f = C("f")
h = D("h")
j = E("j")
e = F("e")
k = B("k")
g = F("g")
i = B("i")
b = B("b")

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