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

class B:
    def __init__(self, txt: str):
        self.t: A = None
        self.txt = txt

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

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

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

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

g = A("g")
c = B("c")
b = C("b")
l = D("l")
k = E("k")
d = F("d")
j = E("j")

g.v = l
c.t = g
b.z = d
b.q = d
b.x = g
b.v = g
b.r = l
l.s = d
k.s = g
k.u = c
k.r = c
k.z = l
k.t = d
k.p = j
d.u = c
d.w = b
d.x = l
j.s = g
j.u = c
j.r = c
j.z = l
j.t = d
j.p = k
assert l.s.u.t.v.txt == "
class A:
    def __init__(self, txt: str):
        self.v: D = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.t: A = None
        self.txt = txt

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

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

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

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

g = A("g")
c = B("c")
b = C("b")
l = D("l")
k = E("k")
d = F("d")
j = E("j")

g.v = l
c.t = g
b.z = d
b.q = d
b.x = g
b.v = g
b.r = l
l.s = d
k.s = g
k.u = c
k.r = c
k.z = l
k.t = d
k.p = j
d.u = c
d.w = b
d.x = l
j.s = g
j.u = c
j.r = c
j.z = l
j.t = d
j.p = k
assert l.s.u.t.v.txt == "l"