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

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

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

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

class E:
    def __init__(self, txt: str):
        self.z: F = None
        self.x: F = None
        self.p: C = None
        self.s: A = None
        self.y: C = None
        self.txt = txt

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

e = A("e")
f = B("f")
i = C("i")
c = D("c")
g = E("g")
k = F("k")
l = F("l")
b = C("b")

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.z: F = None
        self.x: F = None
        self.p: C = None
        self.s: A = None
        self.y: C = None
        self.txt = txt

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

e = A("e")
f = B("f")
i = C("i")
c = D("c")
g = E("g")
k = F("k")
l = F("l")
b = C("b")

e.s = c
e.o = c
e.r = g
e.x = f
e.q = i
f.y = c
f.r = c
f.p = e
f.z = e
f.q = i
f.o = i
i.t = e
i.z = e
i.q = c
i.o = g
i.v = g
i.x = k
c.s = b
c.y = g
c.t = f
c.v = e
g.z = k
g.x = l
g.p = i
g.s = e
g.y = b
k.o = b
k.u = g
l.o = b
l.u = g
b.t = e
b.z = e
b.q = c
b.o = g
b.v = g
b.x = k
assert f.o.q.v.x.p.o.s.txt == "b"