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

class B:
    def __init__(self, txt: str):
        self.s: G = None
        self.t: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.q: I = None
        self.w: J = None
        self.y: J = None
        self.s: D = None
        self.u: I = None
        self.p: E = None
        self.x: E = None
        self.t: H = None
        self.v: H = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.r: C = None
        self.w: A = None
        self.x: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: H = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.p: E = None
        self.txt = txt

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.s: G = None
        self.t: C = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: B = None
        self.q: I = None
        self.w: J = None
        self.y: J = None
        self.s: D = None
        self.u: I = None
        self.p: E = None
        self.x: E = None
        self.t: H = None
        self.v: H = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.r: C = None
        self.w: A = None
        self.x: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.s: H = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.p: E = None
        self.txt = txt

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

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

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

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