class A:
    def __init__(self, txt: str):
        self.x: H = None
        self.t: H = None
        self.p: J = None
        self.txt = txt

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.z: J = None
        self.s: B = None
        self.u: E = None
        self.r: I = None
        self.q: B = None
        self.t: H = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: A = None
        self.t: A = None
        self.q: G = None
        self.w: G = None
        self.txt = txt

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

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

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

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

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

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

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

class F:
    def __init__(self, txt: str):
        self.z: J = None
        self.s: B = None
        self.u: E = None
        self.r: I = None
        self.q: B = None
        self.t: H = None
        self.txt = txt

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

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

class I:
    def __init__(self, txt: str):
        self.v: E = None
        self.u: A = None
        self.t: A = None
        self.q: G = None
        self.w: G = None
        self.txt = txt

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

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

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