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

class B:
    def __init__(self, txt: str):
        self.z: F = None
        self.o: F = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.y: A = None
        self.w: B = None
        self.q: F = None
        self.r: E = None
        self.u: D = None
        self.t: A = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.z: F = None
        self.o: F = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.y: A = None
        self.w: B = None
        self.q: F = None
        self.r: E = None
        self.u: D = None
        self.t: A = None
        self.txt = txt

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

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

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