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

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

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.w: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: A = None
        self.v: B = None
        self.u: A = None
        self.s: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: G = None
        self.s: G = None
        self.x: A = None
        self.w: H = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.u: D = None
        self.t: A = None
        self.txt = txt

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.w: D = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.w: A = None
        self.v: B = None
        self.u: A = None
        self.s: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.o: G = None
        self.s: G = None
        self.x: A = None
        self.w: H = None
        self.txt = txt

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

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

class H:
    def __init__(self, txt: str):
        self.u: D = None
        self.t: A = None
        self.txt = txt

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

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

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

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