class A:
    def __init__(self, txt: str):
        self.r: I = None
        self.y: H = None
        self.x: I = None
        self.w: I = None
        self.o: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.x: E = None
        self.s: I = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.u: H = None
        self.y: C = None
        self.v: E = None
        self.o: B = None
        self.s: C = None
        self.q: A = None
        self.r: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.p: H = None
        self.r: H = None
        self.q: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.v: G = None
        self.z: B = None
        self.q: H = None
        self.o: E = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.s: D = None
        self.p: I = None
        self.y: C = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.x: E = None
        self.s: I = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.u: H = None
        self.y: C = None
        self.v: E = None
        self.o: B = None
        self.s: C = None
        self.q: A = None
        self.r: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: B = None
        self.p: H = None
        self.r: H = None
        self.q: H = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.v: G = None
        self.z: B = None
        self.q: H = None
        self.o: E = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.s: D = None
        self.p: I = None
        self.y: C = None
        self.txt = txt

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

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

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