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

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

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

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

class E:
    def __init__(self, txt: str):
        self.o: D = None
        self.u: D = None
        self.t: C = None
        self.y: D = None
        self.x: A = None
        self.q: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: E = None
        self.u: E = None
        self.s: D = None
        self.o: C = None
        self.txt = txt

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

i = A("i")
e = B("e")
g = C("g")
b = D("b")
a = E("a")
l = F("l")
n = G("n")
f = E("f")
k = E("k")
d = C("d")

i.x = n
i.p = b
i.r = b
i.u = k
i.v = e
e.y = k
e.s = k
e.w = l
e.x = d
g.u = i
b.y = e
b.t = n
a.o = b
a.u = b
a.y = b
a.q = b
a.t = d
a.x = i
l.w = f
l.u = k
l.s = b
l.o = d
n.o = b
f.o = b
f.u = b
f.y = b
f.q = b
f.t = g
f.x = i
k.o = b
k.u = b
k.y = b
k.q = b
k.t = d
k.x = i
d.u = i
assert i.u.x.u.t.u.v.y.x.txt == "
class A:
    def __init__(self, txt: str):
        self.x: G = None
        self.p: D = None
        self.r: D = None
        self.u: E = None
        self.v: B = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.o: D = None
        self.u: D = None
        self.t: C = None
        self.y: D = None
        self.x: A = None
        self.q: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: E = None
        self.u: E = None
        self.s: D = None
        self.o: C = None
        self.txt = txt

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

i = A("i")
e = B("e")
g = C("g")
b = D("b")
a = E("a")
l = F("l")
n = G("n")
f = E("f")
k = E("k")
d = C("d")

i.x = n
i.p = b
i.r = b
i.u = k
i.v = e
e.y = k
e.s = k
e.w = l
e.x = d
g.u = i
b.y = e
b.t = n
a.o = b
a.u = b
a.y = b
a.q = b
a.t = d
a.x = i
l.w = f
l.u = k
l.s = b
l.o = d
n.o = b
f.o = b
f.u = b
f.y = b
f.q = b
f.t = g
f.x = i
k.o = b
k.u = b
k.y = b
k.q = b
k.t = d
k.x = i
d.u = i
assert i.u.x.u.t.u.v.y.x.txt == "i"