class A:
    def __init__(self, txt: str):
        self.z: G = None
        self.u: C = None
        self.r: D = None
        self.x: G = None
        self.p: D = None
        self.y: G = None
        self.txt = txt

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

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.r: A = None
        self.txt = txt

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

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

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

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.r: A = None
        self.txt = txt

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

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