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

class B:
    def __init__(self, txt: str):
        self.r: D = None
        self.p: E = None
        self.s: F = None
        self.y: E = None
        self.q: D = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: F = None
        self.v: G = None
        self.w: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.o: D = None
        self.y: A = None
        self.z: A = None
        self.q: F = None
        self.u: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.r: D = None
        self.p: E = None
        self.s: F = None
        self.y: E = None
        self.q: D = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: F = None
        self.v: G = None
        self.w: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.o: D = None
        self.y: A = None
        self.z: A = None
        self.q: F = None
        self.u: B = None
        self.txt = txt

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

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