class A:
    def __init__(self, txt: str):
        self.y: B = None
        self.v: F = None
        self.w: B = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: G = None
        self.s: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.s: A = None
        self.u: D = None
        self.v: A = None
        self.z: F = None
        self.r: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.p: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.r: A = None
        self.o: C = None
        self.w: D = None
        self.z: E = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.w: G = None
        self.s: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.y: E = None
        self.s: A = None
        self.u: D = None
        self.v: A = None
        self.z: F = None
        self.r: A = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: A = None
        self.p: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.r: A = None
        self.o: C = None
        self.w: D = None
        self.z: E = None
        self.txt = txt

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

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