class A:
    def __init__(self, txt: str):
        self.o: F = None
        self.w: E = None
        self.x: H = None
        self.y: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.o: F = None
        self.q: D = None
        self.p: H = None
        self.w: B = None
        self.u: A = None
        self.t: G = None
        self.r: D = None
        self.y: I = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: H = None
        self.r: G = None
        self.w: F = None
        self.v: H = None
        self.z: B = None
        self.y: F = None
        self.x: A = None
        self.o: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.r: B = None
        self.w: I = None
        self.s: B = None
        self.y: B = None
        self.v: A = None
        self.txt = txt

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

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.o: F = None
        self.q: D = None
        self.p: H = None
        self.w: B = None
        self.u: A = None
        self.t: G = None
        self.r: D = None
        self.y: I = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: H = None
        self.r: G = None
        self.w: F = None
        self.v: H = None
        self.z: B = None
        self.y: F = None
        self.x: A = None
        self.o: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.r: B = None
        self.w: I = None
        self.s: B = None
        self.y: B = None
        self.v: A = None
        self.txt = txt

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

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

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

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

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