class A:
    def __init__(self, txt: str):
        self.r: F = None
        self.t: C = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.s: C = None
        self.txt = txt

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

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

n = A("n")
a = B("a")
j = C("j")
h = D("h")
k = E("k")
b = F("b")
f = G("f")
l = D("l")
e = B("e")

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.s: C = None
        self.txt = txt

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

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

n = A("n")
a = B("a")
j = C("j")
h = D("h")
k = E("k")
b = F("b")
f = G("f")
l = D("l")
e = B("e")

n.r = b
n.t = j
a.x = e
a.z = h
j.v = b
j.r = n
j.x = n
h.t = j
h.y = j
h.u = j
h.p = b
h.s = n
h.o = n
h.q = e
k.s = j
b.w = a
b.x = e
b.v = n
f.p = j
f.w = j
f.o = b
f.x = b
f.u = a
f.t = n
l.t = j
l.y = j
l.u = j
l.p = b
l.s = n
l.o = n
l.q = a
e.x = a
e.z = l
assert n.t.v.v.txt == "n"