class A:
    def __init__(self, txt: str):
        self.x: E = None
        self.v: C = None
        self.t: I = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.t: I = None
        self.q: F = None
        self.r: G = None
        self.v: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: H = None
        self.t: D = None
        self.w: F = None
        self.q: D = None
        self.y: A = None
        self.o: I = None
        self.v: J = None
        self.z: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.q: A = None
        self.z: H = None
        self.t: G = None
        self.p: E = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.y: H = None
        self.x: J = None
        self.t: J = None
        self.v: D = None
        self.w: H = None
        self.u: H = None
        self.s: I = None
        self.o: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: C = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: F = None
        self.r: A = None
        self.s: G = None
        self.y: C = None
        self.q: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.x: H = None
        self.s: B = None
        self.v: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.y: B = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.t: I = None
        self.q: F = None
        self.r: G = None
        self.v: H = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.s: H = None
        self.t: D = None
        self.w: F = None
        self.q: D = None
        self.y: A = None
        self.o: I = None
        self.v: J = None
        self.z: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: C = None
        self.q: A = None
        self.z: H = None
        self.t: G = None
        self.p: E = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.y: H = None
        self.x: J = None
        self.t: J = None
        self.v: D = None
        self.w: H = None
        self.u: H = None
        self.s: I = None
        self.o: D = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: C = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: B = None
        self.x: F = None
        self.r: A = None
        self.s: G = None
        self.y: C = None
        self.q: G = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.x: H = None
        self.s: B = None
        self.v: J = None
        self.txt = txt

class J:
    def __init__(self, txt: str):
        self.y: B = None
        self.txt = txt

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

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