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

class B:
    def __init__(self, txt: str):
        self.y: E = None
        self.o: E = None
        self.v: C = None
        self.p: F = None
        self.u: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.u: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: D = None
        self.t: A = None
        self.z: B = None
        self.q: B = None
        self.v: G = None
        self.u: B = None
        self.s: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: B = None
        self.txt = txt

b = A("b")
i = B("i")
n = C("n")
m = D("m")
j = E("j")
e = F("e")
g = G("g")
h = D("h")
d = A("d")
l = F("l")

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

class B:
    def __init__(self, txt: str):
        self.y: E = None
        self.o: E = None
        self.v: C = None
        self.p: F = None
        self.u: D = None
        self.txt = txt

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

class D:
    def __init__(self, txt: str):
        self.u: B = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.x: D = None
        self.t: A = None
        self.z: B = None
        self.q: B = None
        self.v: G = None
        self.u: B = None
        self.s: B = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: B = None
        self.txt = txt

b = A("b")
i = B("i")
n = C("n")
m = D("m")
j = E("j")
e = F("e")
g = G("g")
h = D("h")
d = A("d")
l = F("l")

b.y = d
b.v = d
b.u = h
b.t = j
b.o = m
b.r = g
b.z = l
i.y = j
i.o = j
i.v = n
i.p = l
i.u = m
n.x = i
n.r = i
n.v = h
n.o = j
m.u = i
j.x = h
j.t = d
j.z = i
j.q = i
j.u = i
j.s = i
j.v = g
e.o = i
g.z = i
h.u = i
d.y = b
d.v = b
d.u = h
d.o = h
d.t = j
d.r = g
d.z = e
l.o = i
assert d.y.t.z.u.txt == "m"