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

class B:
    def __init__(self, txt: str):
        self.s: A = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.z: F = None
        self.q: F = None
        self.t: A = None
        self.u: F = None
        self.txt = txt

e = A("e")
k = B("k")
c = C("c")
n = D("n")
f = E("f")
g = F("g")
h = G("h")
i = D("i")
j = G("j")

e.o = n
e.p = g
e.q = f
e.v = f
k.s = e
c.y = e
c.x = e
c.o = f
n.z = j
n.t = j
n.v = f
n.p = e
n.w = c
n.s = i
f.v = k
f.t = k
f.x = j
f.p = c
f.y = n
g.o = e
g.p = e
g.v = f
g.w = c
g.u = h
h.z = g
h.q = g
h.u = g
h.t = e
i.z = j
i.t = j
i.v = f
i.p = e
i.w = c
i.s = n
j.z = g
j.q = g
j.u = g
j.t = e
assert e.o.t.t.txt == "
class A:
    def __init__(self, txt: str):
        self.o: D = None
        self.p: F = None
        self.q: E = None
        self.v: E = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.s: A = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.z: F = None
        self.q: F = None
        self.t: A = None
        self.u: F = None
        self.txt = txt

e = A("e")
k = B("k")
c = C("c")
n = D("n")
f = E("f")
g = F("g")
h = G("h")
i = D("i")
j = G("j")

e.o = n
e.p = g
e.q = f
e.v = f
k.s = e
c.y = e
c.x = e
c.o = f
n.z = j
n.t = j
n.v = f
n.p = e
n.w = c
n.s = i
f.v = k
f.t = k
f.x = j
f.p = c
f.y = n
g.o = e
g.p = e
g.v = f
g.w = c
g.u = h
h.z = g
h.q = g
h.u = g
h.t = e
i.z = j
i.t = j
i.v = f
i.p = e
i.w = c
i.s = n
j.z = g
j.q = g
j.u = g
j.t = e
assert e.o.t.t.txt == "e"