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

class B:
    def __init__(self, txt: str):
        self.v: G = None
        self.s: C = None
        self.y: D = None
        self.r: D = None
        self.o: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: I = None
        self.s: E = None
        self.w: H = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: D = None
        self.u: F = None
        self.s: G = None
        self.z: H = None
        self.w: C = None
        self.o: D = None
        self.v: A = None
        self.q: H = None
        self.t: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: H = None
        self.x: B = None
        self.p: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: A = None
        self.o: C = None
        self.w: C = None
        self.v: F = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.v: G = None
        self.s: C = None
        self.y: D = None
        self.r: D = None
        self.o: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: I = None
        self.s: E = None
        self.w: H = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.p: D = None
        self.u: F = None
        self.s: G = None
        self.z: H = None
        self.w: C = None
        self.o: D = None
        self.v: A = None
        self.q: H = None
        self.t: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.q: H = None
        self.x: B = None
        self.p: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.u: A = None
        self.o: C = None
        self.w: C = None
        self.v: F = None
        self.txt = txt

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

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

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