class A:
    def __init__(self, txt: str):
        self.v: A = None
        self.r: F = None
        self.o: A = None
        self.p: D = None
        self.q: E = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.w: A = None
        self.y: C = None
        self.r: B = None
        self.o: F = None
        self.v: B = None
        self.txt = txt

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

c = A("c")
k = B("k")
d = C("d")
e = D("e")
l = E("l")
i = F("i")
f = A("f")
j = E("j")
b = D("b")

c.v = f
c.o = f
c.r = i
c.p = b
c.q = j
k.s = b
k.w = i
d.t = c
d.y = i
d.o = k
d.s = b
e.z = i
e.y = j
e.w = b
e.r = b
e.u = k
l.w = f
l.y = d
l.r = k
l.v = k
l.o = i
i.u = c
i.p = f
i.t = b
i.s = k
i.w = j
i.y = l
f.v = c
f.o = c
f.r = i
f.p = e
f.q = l
j.w = c
j.y = d
j.r = k
j.v = k
j.o = i
b.z = i
b.y = j
b.w = e
b.r = e
b.u = k
assert e.y.y.s.r.txt == "
class A:
    def __init__(self, txt: str):
        self.v: A = None
        self.r: F = None
        self.o: A = None
        self.p: D = None
        self.q: E = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.w: A = None
        self.y: C = None
        self.r: B = None
        self.o: F = None
        self.v: B = None
        self.txt = txt

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

c = A("c")
k = B("k")
d = C("d")
e = D("e")
l = E("l")
i = F("i")
f = A("f")
j = E("j")
b = D("b")

c.v = f
c.o = f
c.r = i
c.p = b
c.q = j
k.s = b
k.w = i
d.t = c
d.y = i
d.o = k
d.s = b
e.z = i
e.y = j
e.w = b
e.r = b
e.u = k
l.w = f
l.y = d
l.r = k
l.v = k
l.o = i
i.u = c
i.p = f
i.t = b
i.s = k
i.w = j
i.y = l
f.v = c
f.o = c
f.r = i
f.p = e
f.q = l
j.w = c
j.y = d
j.r = k
j.v = k
j.o = i
b.z = i
b.y = j
b.w = e
b.r = e
b.u = k
assert e.y.y.s.r.txt == "e"