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

class B:
    def __init__(self, txt: str):
        self.u: F = None
        self.v: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: J = None
        self.q: E = None
        self.t: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: I = None
        self.y: G = None
        self.p: E = None
        self.t: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: J = None
        self.y: G = None
        self.u: B = None
        self.t: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: B = None
        self.t: C = None
        self.z: I = None
        self.o: D = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: G = None
        self.r: J = None
        self.o: A = None
        self.w: B = None
        self.p: G = None
        self.z: A = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: A = None
        self.y: A = None
        self.u: J = None
        self.s: G = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.u: F = None
        self.v: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: J = None
        self.q: E = None
        self.t: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: I = None
        self.y: G = None
        self.p: E = None
        self.t: I = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: J = None
        self.y: G = None
        self.u: B = None
        self.t: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: B = None
        self.t: C = None
        self.z: I = None
        self.o: D = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.s: G = None
        self.r: J = None
        self.o: A = None
        self.w: B = None
        self.p: G = None
        self.z: A = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.p: A = None
        self.y: A = None
        self.u: J = None
        self.s: G = None
        self.txt = txt

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

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

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