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

class B:
    def __init__(self, txt: str):
        self.o: D = None
        self.r: G = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.x: G = None
        self.s: E = None
        self.p: B = None
        self.r: D = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.u: B = None
        self.t: B = None
        self.o: D = None
        self.txt = txt

l = A("l")
j = B("j")
k = C("k")
e = D("e")
i = E("i")
n = F("n")
g = G("g")
c = D("c")

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

class B:
    def __init__(self, txt: str):
        self.o: D = None
        self.r: G = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.x: G = None
        self.s: E = None
        self.p: B = None
        self.r: D = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.x: B = None
        self.u: B = None
        self.t: B = None
        self.o: D = None
        self.txt = txt

l = A("l")
j = B("j")
k = C("k")
e = D("e")
i = E("i")
n = F("n")
g = G("g")
c = D("c")

l.r = g
l.p = i
l.t = i
l.v = c
j.o = e
j.r = g
k.s = i
k.t = i
k.v = c
k.o = j
e.x = g
e.s = i
e.p = j
e.r = c
i.u = j
i.t = j
i.w = j
i.z = k
i.y = l
n.v = k
n.w = i
n.r = e
n.y = j
g.x = j
g.u = j
g.t = j
g.o = e
c.x = g
c.s = i
c.p = j
c.r = e
assert i.z.t.z.v.r.s.txt == "i"