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

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

class C:
    def __init__(self, txt: str):
        self.r: A = None
        self.x: B = None
        self.s: D = None
        self.w: F = None
        self.p: F = None
        self.u: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.u: F = None
        self.txt = txt

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.r: A = None
        self.x: B = None
        self.s: D = None
        self.w: F = None
        self.p: F = None
        self.u: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.u: F = None
        self.txt = txt

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

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

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

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