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

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.o: A = None
        self.u: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: E = None
        self.s: C = None
        self.y: F = None
        self.t: C = None
        self.q: F = None
        self.u: E = None
        self.txt = txt

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

c = A("c")
h = B("h")
j = C("j")
k = D("k")
i = E("i")
n = F("n")
d = B("d")
a = E("a")
e = C("e")
m = E("m")

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

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

class C:
    def __init__(self, txt: str):
        self.t: F = None
        self.o: A = None
        self.u: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: E = None
        self.s: C = None
        self.y: F = None
        self.t: C = None
        self.q: F = None
        self.u: E = None
        self.txt = txt

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

c = A("c")
h = B("h")
j = C("j")
k = D("k")
i = E("i")
n = F("n")
d = B("d")
a = E("a")
e = C("e")
m = E("m")

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