class A:
    def __init__(self, txt: str):
        self.y: F = None
        self.x: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.s: C = None
        self.x: C = None
        self.y: D = None
        self.v: C = None
        self.z: A = None
        self.u: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.y: C = None
        self.s: E = None
        self.t: I = None
        self.r: F = None
        self.z: A = None
        self.x: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.p: C = None
        self.t: D = None
        self.v: E = None
        self.z: C = None
        self.w: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: C = None
        self.v: E = None
        self.t: D = None
        self.s: H = None
        self.z: B = None
        self.w: C = None
        self.u: C = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: C = None
        self.q: A = None
        self.w: B = None
        self.u: H = None
        self.z: C = None
        self.txt = txt

c = A("c")
b = B("b")
f = C("f")
d = D("d")
i = E("i")
j = F("j")
m = G("m")
k = H("k")
n = I("n")
h = G("h")

c.y = j
c.x = f
b.s = f
b.x = f
b.v = f
b.y = d
b.u = d
b.z = c
f.s = j
f.r = m
f.v = h
f.t = d
d.y = f
d.s = i
d.t = n
d.r = j
d.z = c
d.x = k
i.t = d
i.u = b
i.v = b
i.x = f
i.r = m
i.y = m
i.z = k
i.o = c
j.x = b
j.p = f
j.z = f
j.t = d
j.v = i
j.w = k
m.x = f
m.w = f
m.u = f
m.v = i
m.t = d
m.s = k
m.z = b
k.y = c
n.t = f
n.z = f
n.q = c
n.w = b
n.u = k
h.x = f
h.w = f
h.u = f
h.v = i
h.t = d
h.s = k
h.z = b
assert j.v.r.s.y.x.s.z.t.s.txt == "
class A:
    def __init__(self, txt: str):
        self.y: F = None
        self.x: C = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.s: C = None
        self.x: C = None
        self.y: D = None
        self.v: C = None
        self.z: A = None
        self.u: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.y: C = None
        self.s: E = None
        self.t: I = None
        self.r: F = None
        self.z: A = None
        self.x: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.x: B = None
        self.p: C = None
        self.t: D = None
        self.v: E = None
        self.z: C = None
        self.w: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.x: C = None
        self.v: E = None
        self.t: D = None
        self.s: H = None
        self.z: B = None
        self.w: C = None
        self.u: C = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.t: C = None
        self.q: A = None
        self.w: B = None
        self.u: H = None
        self.z: C = None
        self.txt = txt

c = A("c")
b = B("b")
f = C("f")
d = D("d")
i = E("i")
j = F("j")
m = G("m")
k = H("k")
n = I("n")
h = G("h")

c.y = j
c.x = f
b.s = f
b.x = f
b.v = f
b.y = d
b.u = d
b.z = c
f.s = j
f.r = m
f.v = h
f.t = d
d.y = f
d.s = i
d.t = n
d.r = j
d.z = c
d.x = k
i.t = d
i.u = b
i.v = b
i.x = f
i.r = m
i.y = m
i.z = k
i.o = c
j.x = b
j.p = f
j.z = f
j.t = d
j.v = i
j.w = k
m.x = f
m.w = f
m.u = f
m.v = i
m.t = d
m.s = k
m.z = b
k.y = c
n.t = f
n.z = f
n.q = c
n.w = b
n.u = k
h.x = f
h.w = f
h.u = f
h.v = i
h.t = d
h.s = k
h.z = b
assert j.v.r.s.y.x.s.z.t.s.txt == "i"