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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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