class A:
    def __init__(self, txt: str):
        self.v: G = None
        self.r: F = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.r: F = None
        self.txt = txt

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

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

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

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

class J:
    def __init__(self, txt: str):
        self.t: G = None
        self.txt = txt

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.r: F = None
        self.txt = txt

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

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

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

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

class J:
    def __init__(self, txt: str):
        self.t: G = None
        self.txt = txt

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

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