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

class B:
    def __init__(self, txt: str):
        self.v: E = None
        self.y: E = None
        self.r: E = None
        self.t: C = None
        self.u: B = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.z: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.t: C = None
        self.r: D = None
        self.o: A = None
        self.txt = txt

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

e = A("e")
h = B("h")
a = C("a")
c = D("c")
g = E("g")
k = F("k")
n = B("n")
l = B("l")
m = A("m")
f = F("f")

e.x = c
e.w = f
e.y = a
e.z = n
h.v = g
h.y = g
h.r = g
h.t = a
h.u = n
a.z = k
a.v = k
a.x = h
a.p = m
a.o = g
c.z = m
g.v = c
g.r = c
g.t = a
g.o = e
k.s = n
k.r = f
n.v = g
n.y = g
n.r = g
n.t = a
n.u = l
l.v = g
l.y = g
l.r = g
l.t = a
l.u = h
m.x = c
m.w = k
m.y = a
m.z = h
f.s = l
f.r = k
assert g.t.p.y.txt == "
class A:
    def __init__(self, txt: str):
        self.x: D = None
        self.w: F = None
        self.y: C = None
        self.z: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.v: E = None
        self.y: E = None
        self.r: E = None
        self.t: C = None
        self.u: B = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.z: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.v: D = None
        self.t: C = None
        self.r: D = None
        self.o: A = None
        self.txt = txt

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

e = A("e")
h = B("h")
a = C("a")
c = D("c")
g = E("g")
k = F("k")
n = B("n")
l = B("l")
m = A("m")
f = F("f")

e.x = c
e.w = f
e.y = a
e.z = n
h.v = g
h.y = g
h.r = g
h.t = a
h.u = n
a.z = k
a.v = k
a.x = h
a.p = m
a.o = g
c.z = m
g.v = c
g.r = c
g.t = a
g.o = e
k.s = n
k.r = f
n.v = g
n.y = g
n.r = g
n.t = a
n.u = l
l.v = g
l.y = g
l.r = g
l.t = a
l.u = h
m.x = c
m.w = k
m.y = a
m.z = h
f.s = l
f.r = k
assert g.t.p.y.txt == "a"