class A:
    def __init__(self, txt: str):
        self.v: H = None
        self.t: F = None
        self.u: G = None
        self.s: I = None
        self.z: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.p: E = None
        self.q: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.w: D = None
        self.t: D = None
        self.q: A = None
        self.s: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: C = None
        self.u: I = None
        self.v: I = None
        self.r: C = None
        self.p: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: H = None
        self.q: D = None
        self.r: D = None
        self.z: A = None
        self.x: A = None
        self.txt = txt

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

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.p: E = None
        self.q: I = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.w: D = None
        self.t: D = None
        self.q: A = None
        self.s: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.z: C = None
        self.u: I = None
        self.v: I = None
        self.r: C = None
        self.p: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: H = None
        self.q: D = None
        self.r: D = None
        self.z: A = None
        self.x: A = None
        self.txt = txt

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

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

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

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