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

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

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

class D:
    def __init__(self, txt: str):
        self.x: E = None
        self.z: A = None
        self.t: I = None
        self.p: A = None
        self.u: A = None
        self.r: J = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.x: C = None
        self.txt = txt

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

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

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.x: E = None
        self.z: A = None
        self.t: I = None
        self.p: A = None
        self.u: A = None
        self.r: J = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.x: C = None
        self.txt = txt

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

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

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

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