class A:
    def __init__(self, txt: str):
        self.p: D = None
        self.z: F = None
        self.v: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.s: D = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.q: C = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.s: E = None
        self.x: A = None
        self.q: G = None
        self.o: B = None
        self.v: E = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.s: D = None
        self.txt = txt

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

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

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

class G:
    def __init__(self, txt: str):
        self.q: C = None
        self.txt = txt

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

class I:
    def __init__(self, txt: str):
        self.s: E = None
        self.x: A = None
        self.q: G = None
        self.o: B = None
        self.v: E = None
        self.txt = txt

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

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