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

class B:
    def __init__(self, txt: str):
        self.y: E = None
        self.txt = txt

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

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.y: E = None
        self.txt = txt

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

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

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

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

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

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