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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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