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

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

class C:
    def __init__(self, txt: str):
        self.x: A = None
        self.o: G = None
        self.p: B = None
        self.r: B = None
        self.v: B = None
        self.z: I = None
        self.t: G = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.y: A = None
        self.v: F = None
        self.q: H = None
        self.z: E = None
        self.s: E = None
        self.o: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.r: F = None
        self.z: F = None
        self.u: F = None
        self.p: A = None
        self.t: I = None
        self.s: C = None
        self.q: B = None
        self.o: A = None
        self.txt = txt

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

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

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

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

class C:
    def __init__(self, txt: str):
        self.x: A = None
        self.o: G = None
        self.p: B = None
        self.r: B = None
        self.v: B = None
        self.z: I = None
        self.t: G = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.y: A = None
        self.v: F = None
        self.q: H = None
        self.z: E = None
        self.s: E = None
        self.o: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.r: F = None
        self.z: F = None
        self.u: F = None
        self.p: A = None
        self.t: I = None
        self.s: C = None
        self.q: B = None
        self.o: A = None
        self.txt = txt

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

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

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