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

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

class C:
    def __init__(self, txt: str):
        self.q: B = None
        self.t: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: F = None
        self.x: A = None
        self.r: C = None
        self.s: F = None
        self.u: A = None
        self.w: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.r: A = None
        self.w: B = None
        self.v: F = None
        self.z: B = None
        self.o: F = None
        self.y: E = None
        self.txt = txt

l = A("l")
a = B("a")
k = C("k")
f = D("f")
m = E("m")
j = F("j")
i = A("i")
b = F("b")

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

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

class C:
    def __init__(self, txt: str):
        self.q: B = None
        self.t: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: F = None
        self.x: A = None
        self.r: C = None
        self.s: F = None
        self.u: A = None
        self.w: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.r: A = None
        self.w: B = None
        self.v: F = None
        self.z: B = None
        self.o: F = None
        self.y: E = None
        self.txt = txt

l = A("l")
a = B("a")
k = C("k")
f = D("f")
m = E("m")
j = F("j")
i = A("i")
b = F("b")

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