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

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

class C:
    def __init__(self, txt: str):
        self.q: E = None
        self.s: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: A = None
        self.q: B = None
        self.y: B = None
        self.txt = txt

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.q: E = None
        self.s: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.p: A = None
        self.q: B = None
        self.y: B = None
        self.txt = txt

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

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

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

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