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

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

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

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

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.o: C = None
        self.y: C = None
        self.q: C = None
        self.z: D = None
        self.t: B = None
        self.txt = txt

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

e = A("e")
f = B("f")
c = C("c")
h = D("h")
n = E("n")
m = F("m")
k = D("k")
b = F("b")

e.s = f
f.o = b
f.t = e
c.z = k
c.u = f
c.q = e
c.o = e
c.v = n
h.q = f
h.y = n
h.o = e
n.r = e
n.o = c
n.y = c
n.q = c
n.z = h
n.t = f
m.q = f
m.s = f
m.u = k
m.v = c
m.y = b
m.t = h
k.q = f
k.y = n
k.o = e
b.q = f
b.s = f
b.u = k
b.v = c
b.y = m
b.t = h
assert f.t.s.o.s.txt == "
class A:
    def __init__(self, txt: str):
        self.s: B = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.r: A = None
        self.o: C = None
        self.y: C = None
        self.q: C = None
        self.z: D = None
        self.t: B = None
        self.txt = txt

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

e = A("e")
f = B("f")
c = C("c")
h = D("h")
n = E("n")
m = F("m")
k = D("k")
b = F("b")

e.s = f
f.o = b
f.t = e
c.z = k
c.u = f
c.q = e
c.o = e
c.v = n
h.q = f
h.y = n
h.o = e
n.r = e
n.o = c
n.y = c
n.q = c
n.z = h
n.t = f
m.q = f
m.s = f
m.u = k
m.v = c
m.y = b
m.t = h
k.q = f
k.y = n
k.o = e
b.q = f
b.s = f
b.u = k
b.v = c
b.y = m
b.t = h
assert f.t.s.o.s.txt == "f"