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

class B:
    def __init__(self, txt: str):
        self.o: D = None
        self.v: G = None
        self.t: D = None
        self.r: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.t: F = None
        self.p: G = None
        self.z: E = None
        self.s: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: D = None
        self.x: G = None
        self.o: D = None
        self.u: E = None
        self.w: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: F = None
        self.t: D = None
        self.x: B = None
        self.s: B = None
        self.q: C = None
        self.o: B = None
        self.z: B = None
        self.txt = txt

j = A("j")
f = B("f")
i = C("i")
k = D("k")
d = E("d")
e = F("e")
l = G("l")
b = C("b")

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

class B:
    def __init__(self, txt: str):
        self.o: D = None
        self.v: G = None
        self.t: D = None
        self.r: C = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.v: E = None
        self.t: F = None
        self.p: G = None
        self.z: E = None
        self.s: C = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: D = None
        self.x: G = None
        self.o: D = None
        self.u: E = None
        self.w: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: F = None
        self.t: D = None
        self.x: B = None
        self.s: B = None
        self.q: C = None
        self.o: B = None
        self.z: B = None
        self.txt = txt

j = A("j")
f = B("f")
i = C("i")
k = D("k")
d = E("d")
e = F("e")
l = G("l")
b = C("b")

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