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

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

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

class D:
    def __init__(self, txt: str):
        self.s: J = None
        self.z: B = None
        self.p: I = None
        self.q: B = None
        self.w: C = None
        self.t: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.o: J = None
        self.v: B = None
        self.x: B = None
        self.s: H = None
        self.z: E = None
        self.y: H = None
        self.t: B = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.p: D = None
        self.z: E = None
        self.txt = txt

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.s: J = None
        self.z: B = None
        self.p: I = None
        self.q: B = None
        self.w: C = None
        self.t: I = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.o: J = None
        self.v: B = None
        self.x: B = None
        self.s: H = None
        self.z: E = None
        self.y: H = None
        self.t: B = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.p: D = None
        self.z: E = None
        self.txt = txt

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

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