class A:
    def __init__(self, txt: str):
        self.t: I = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.s: E = None
        self.v: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.w: H = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.p: B = None
        self.x: H = None
        self.r: B = None
        self.v: G = None
        self.q: A = None
        self.z: A = None
        self.u: D = None
        self.w: F = None
        self.txt = txt

i = A("i")
e = B("e")
j = C("j")
d = D("d")
l = E("l")
b = F("b")
g = G("g")
m = H("m")
f = I("f")
n = I("n")

i.t = n
e.w = g
e.z = b
e.s = b
e.u = i
j.s = l
j.v = l
d.x = b
d.r = f
l.t = d
b.o = d
g.w = m
m.u = d
f.p = e
f.r = e
f.x = m
f.v = g
f.q = i
f.z = i
f.u = d
f.w = b
n.p = e
n.r = e
n.x = m
n.v = g
n.q = i
n.z = i
n.u = d
n.w = b
assert l.t.x.o.x.o.txt == "
class A:
    def __init__(self, txt: str):
        self.t: I = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.s: E = None
        self.v: E = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.w: H = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.p: B = None
        self.x: H = None
        self.r: B = None
        self.v: G = None
        self.q: A = None
        self.z: A = None
        self.u: D = None
        self.w: F = None
        self.txt = txt

i = A("i")
e = B("e")
j = C("j")
d = D("d")
l = E("l")
b = F("b")
g = G("g")
m = H("m")
f = I("f")
n = I("n")

i.t = n
e.w = g
e.z = b
e.s = b
e.u = i
j.s = l
j.v = l
d.x = b
d.r = f
l.t = d
b.o = d
g.w = m
m.u = d
f.p = e
f.r = e
f.x = m
f.v = g
f.q = i
f.z = i
f.u = d
f.w = b
n.p = e
n.r = e
n.x = m
n.v = g
n.q = i
n.z = i
n.u = d
n.w = b
assert l.t.x.o.x.o.txt == "d"