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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.r: D = None
        self.q: G = None
        self.p: B = None
        self.z: G = None
        self.w: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.s: B = None
        self.txt = txt

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

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.r: D = None
        self.q: G = None
        self.p: B = None
        self.z: G = None
        self.w: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.s: B = None
        self.txt = txt

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

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