class A:
    def __init__(self, txt: str):
        self.o: E = None
        self.s: J = None
        self.t: I = None
        self.p: C = None
        self.y: H = None
        self.r: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.s: E = None
        self.u: D = None
        self.p: F = None
        self.z: J = None
        self.v: I = None
        self.o: D = None
        self.t: F = None
        self.y: C = None
        self.r: A = None
        self.q: A = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: I = None
        self.p: F = None
        self.w: F = None
        self.z: F = None
        self.r: D = None
        self.y: G = None
        self.q: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: C = None
        self.t: D = None
        self.p: G = None
        self.r: C = None
        self.o: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.o: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: C = None
        self.w: B = None
        self.p: J = None
        self.x: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: H = None
        self.p: A = None
        self.v: J = None
        self.txt = txt

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

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

d.o = m
d.s = a
d.t = f
d.p = c
d.y = n
d.r = l
l.s = m
l.u = k
l.o = k
l.p = b
l.t = b
l.z = a
l.v = f
l.y = c
l.r = d
l.q = d
c.o = f
c.u = f
c.z = f
c.x = d
c.s = d
c.r = k
c.p = n
c.t = a
k.s = b
m.o = f
m.q = f
m.p = b
m.w = b
m.z = b
m.r = k
m.y = h
b.x = c
b.y = c
b.r = c
b.t = k
b.p = h
b.o = n
h.o = m
n.u = c
n.w = l
n.p = a
n.x = b
f.w = n
f.p = d
f.v = a
a.p = k
a.u = k
a.x = n
assert l.z.u.s.t.s.o.p.u.s.txt == "
class A:
    def __init__(self, txt: str):
        self.o: E = None
        self.s: J = None
        self.t: I = None
        self.p: C = None
        self.y: H = None
        self.r: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.s: E = None
        self.u: D = None
        self.p: F = None
        self.z: J = None
        self.v: I = None
        self.o: D = None
        self.t: F = None
        self.y: C = None
        self.r: A = None
        self.q: A = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: I = None
        self.p: F = None
        self.w: F = None
        self.z: F = None
        self.r: D = None
        self.y: G = None
        self.q: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.x: C = None
        self.y: C = None
        self.t: D = None
        self.p: G = None
        self.r: C = None
        self.o: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.o: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: C = None
        self.w: B = None
        self.p: J = None
        self.x: F = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.w: H = None
        self.p: A = None
        self.v: J = None
        self.txt = txt

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

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

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