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

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

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

class D:
    def __init__(self, txt: str):
        self.z: E = None
        self.o: E = None
        self.txt = txt

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

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

k = A("k")
j = B("j")
i = C("i")
n = D("n")
g = E("g")
d = F("d")
c = B("c")
b = F("b")

k.t = i
j.o = g
j.w = i
i.r = n
i.o = g
i.v = b
i.x = b
n.z = g
n.o = g
g.q = c
g.s = n
g.o = k
g.v = k
g.p = d
d.p = c
d.q = c
d.t = n
d.z = n
d.r = k
d.u = i
c.o = g
c.w = i
b.p = c
b.t = n
b.z = n
b.q = j
b.r = k
b.u = i
assert d.q.o.q.o.v.t.x.txt == "
class A:
    def __init__(self, txt: str):
        self.t: C = None
        self.txt = txt

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

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

class D:
    def __init__(self, txt: str):
        self.z: E = None
        self.o: E = None
        self.txt = txt

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

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

k = A("k")
j = B("j")
i = C("i")
n = D("n")
g = E("g")
d = F("d")
c = B("c")
b = F("b")

k.t = i
j.o = g
j.w = i
i.r = n
i.o = g
i.v = b
i.x = b
n.z = g
n.o = g
g.q = c
g.s = n
g.o = k
g.v = k
g.p = d
d.p = c
d.q = c
d.t = n
d.z = n
d.r = k
d.u = i
c.o = g
c.w = i
b.p = c
b.t = n
b.z = n
b.q = j
b.r = k
b.u = i
assert d.q.o.q.o.v.t.x.txt == "b"