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

class B:
    def __init__(self, txt: str):
        self.s: G = None
        self.o: E = None
        self.z: D = None
        self.p: A = None
        self.x: D = None
        self.r: G = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: B = None
        self.txt = txt

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

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

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

l = A("l")
i = B("i")
j = C("j")
m = D("m")
b = E("b")
a = F("a")
n = G("n")
e = E("e")
k = C("k")
c = D("c")

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

class B:
    def __init__(self, txt: str):
        self.s: G = None
        self.o: E = None
        self.z: D = None
        self.p: A = None
        self.x: D = None
        self.r: G = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: B = None
        self.txt = txt

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

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

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

l = A("l")
i = B("i")
j = C("j")
m = D("m")
b = E("b")
a = F("a")
n = G("n")
e = E("e")
k = C("k")
c = D("c")

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