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

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

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

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: E = None
        self.t: A = None
        self.v: F = None
        self.q: E = None
        self.u: A = None
        self.txt = txt

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

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: E = None
        self.t: A = None
        self.v: F = None
        self.q: E = None
        self.u: A = None
        self.txt = txt

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

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

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

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