class A:
    def __init__(self, txt: str):
        self.o: D = None
        self.x: H = None
        self.r: C = None
        self.u: G = None
        self.z: I = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.t: B = None
        self.v: I = None
        self.o: I = None
        self.z: B = None
        self.u: H = None
        self.y: F = None
        self.x: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: I = None
        self.u: I = None
        self.w: B = None
        self.p: C = None
        self.r: C = None
        self.y: C = None
        self.z: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: H = None
        self.t: C = None
        self.w: C = None
        self.u: D = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.v: F = None
        self.r: D = None
        self.z: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: E = None
        self.txt = txt

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

j = A("j")
i = B("i")
g = C("g")
l = D("l")
c = E("c")
n = F("n")
m = G("m")
k = H("k")
a = I("a")

j.o = l
j.x = k
j.r = g
j.u = m
j.z = a
i.y = m
g.w = i
g.t = i
g.z = i
g.x = i
g.v = a
g.o = a
g.u = k
g.y = n
l.v = a
l.u = a
l.w = i
l.p = g
l.r = g
l.y = g
l.z = k
c.p = k
c.t = g
c.w = g
c.u = l
n.t = a
n.o = l
m.v = n
m.r = l
m.z = j
k.y = c
a.s = n
a.w = g
a.u = j
assert l.u.w.t.txt == "
class A:
    def __init__(self, txt: str):
        self.o: D = None
        self.x: H = None
        self.r: C = None
        self.u: G = None
        self.z: I = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.t: B = None
        self.v: I = None
        self.o: I = None
        self.z: B = None
        self.u: H = None
        self.y: F = None
        self.x: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: I = None
        self.u: I = None
        self.w: B = None
        self.p: C = None
        self.r: C = None
        self.y: C = None
        self.z: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.p: H = None
        self.t: C = None
        self.w: C = None
        self.u: D = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.v: F = None
        self.r: D = None
        self.z: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: E = None
        self.txt = txt

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

j = A("j")
i = B("i")
g = C("g")
l = D("l")
c = E("c")
n = F("n")
m = G("m")
k = H("k")
a = I("a")

j.o = l
j.x = k
j.r = g
j.u = m
j.z = a
i.y = m
g.w = i
g.t = i
g.z = i
g.x = i
g.v = a
g.o = a
g.u = k
g.y = n
l.v = a
l.u = a
l.w = i
l.p = g
l.r = g
l.y = g
l.z = k
c.p = k
c.t = g
c.w = g
c.u = l
n.t = a
n.o = l
m.v = n
m.r = l
m.z = j
k.y = c
a.s = n
a.w = g
a.u = j
assert l.u.w.t.txt == "i"