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

class B:
    def __init__(self, txt: str):
        self.p: E = None
        self.q: A = None
        self.o: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.x: E = None
        self.s: B = None
        self.p: D = None
        self.t: D = None
        self.u: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.v: E = None
        self.y: D = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.p: E = None
        self.q: A = None
        self.o: E = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.x: E = None
        self.s: B = None
        self.p: D = None
        self.t: D = None
        self.u: F = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.t: D = None
        self.v: E = None
        self.y: D = None
        self.txt = txt

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

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