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

class B:
    def __init__(self, txt: str):
        self.o: H = None
        self.p: F = None
        self.x: F = None
        self.z: J = None
        self.t: G = None
        self.u: H = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.r: B = None
        self.z: E = None
        self.p: B = None
        self.v: A = None
        self.q: F = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.r: E = None
        self.p: E = None
        self.z: G = None
        self.v: J = None
        self.s: F = None
        self.w: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.v: F = None
        self.p: A = None
        self.y: H = None
        self.u: C = None
        self.r: A = None
        self.q: D = None
        self.w: D = None
        self.s: G = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.o: H = None
        self.p: F = None
        self.x: F = None
        self.z: J = None
        self.t: G = None
        self.u: H = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.r: B = None
        self.z: E = None
        self.p: B = None
        self.v: A = None
        self.q: F = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.r: E = None
        self.p: E = None
        self.z: G = None
        self.v: J = None
        self.s: F = None
        self.w: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.v: F = None
        self.p: A = None
        self.y: H = None
        self.u: C = None
        self.r: A = None
        self.q: D = None
        self.w: D = None
        self.s: G = None
        self.txt = txt

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

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