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

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

class C:
    def __init__(self, txt: str):
        self.p: E = None
        self.o: E = None
        self.x: J = None
        self.s: H = None
        self.y: G = None
        self.u: A = None
        self.r: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.t: E = None
        self.u: A = None
        self.o: F = None
        self.r: A = None
        self.y: C = None
        self.v: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: C = None
        self.r: C = None
        self.t: H = None
        self.q: I = None
        self.o: F = None
        self.w: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: D = None
        self.o: I = None
        self.r: A = None
        self.q: D = None
        self.p: A = None
        self.v: E = None
        self.t: H = None
        self.x: J = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.x: J = None
        self.v: B = None
        self.w: I = None
        self.u: F = None
        self.t: A = None
        self.q: B = None
        self.o: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.t: H = None
        self.z: H = None
        self.o: G = None
        self.v: A = None
        self.w: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: A = None
        self.s: G = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.p: E = None
        self.o: E = None
        self.x: J = None
        self.s: H = None
        self.y: G = None
        self.u: A = None
        self.r: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.t: E = None
        self.u: A = None
        self.o: F = None
        self.r: A = None
        self.y: C = None
        self.v: E = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: C = None
        self.r: C = None
        self.t: H = None
        self.q: I = None
        self.o: F = None
        self.w: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: D = None
        self.o: I = None
        self.r: A = None
        self.q: D = None
        self.p: A = None
        self.v: E = None
        self.t: H = None
        self.x: J = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.x: J = None
        self.v: B = None
        self.w: I = None
        self.u: F = None
        self.t: A = None
        self.q: B = None
        self.o: E = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.t: H = None
        self.z: H = None
        self.o: G = None
        self.v: A = None
        self.w: D = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.z: A = None
        self.s: G = None
        self.txt = txt

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

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