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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

b.u = l
b.s = g
b.o = i
k.t = f
k.y = f
k.s = b
k.q = l
h.q = m
h.p = f
e.r = f
e.u = f
e.y = f
e.s = l
n.o = f
f.y = h
f.w = h
f.q = n
f.z = i
f.p = k
f.r = b
g.r = f
g.x = f
g.t = b
g.q = b
g.p = e
g.s = i
g.z = l
m.r = f
m.x = f
m.t = b
m.q = b
m.p = e
m.s = g
m.z = l
i.r = f
i.x = f
i.t = b
i.q = b
i.p = e
i.s = g
i.z = l
l.t = f
l.y = f
l.s = b
l.q = k
assert g.t.o.z.s.u.q.s.u.s.txt == "b"