class A:
    def __init__(self, txt: str):
        self.z: B = None
        self.s: E = None
        self.v: A = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: A = None
        self.z: B = None
        self.v: D = None
        self.r: A = None
        self.u: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.q: F = None
        self.y: D = None
        self.x: A = None
        self.z: B = None
        self.r: C = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.t: D = None
        self.p: A = None
        self.z: B = None
        self.v: D = None
        self.r: A = None
        self.u: A = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.q: F = None
        self.y: D = None
        self.x: A = None
        self.z: B = None
        self.r: C = None
        self.txt = txt

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

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

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