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

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

class C:
    def __init__(self, txt: str):
        self.o: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: H = None
        self.t: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: H = None
        self.v: A = None
        self.x: E = None
        self.p: A = None
        self.q: C = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.q: A = None
        self.t: A = None
        self.v: G = None
        self.p: I = None
        self.y: H = None
        self.o: D = None
        self.x: A = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.o: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: A = None
        self.x: H = None
        self.t: A = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: H = None
        self.v: A = None
        self.x: E = None
        self.p: A = None
        self.q: C = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.q: A = None
        self.t: A = None
        self.v: G = None
        self.p: I = None
        self.y: H = None
        self.o: D = None
        self.x: A = None
        self.txt = txt

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

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