class A:
    def __init__(self, txt: str):
        self.o: G = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.x: C = None
        self.z: C = None
        self.txt = txt

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

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

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.x: C = None
        self.z: C = None
        self.txt = txt

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

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

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

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