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

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

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

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

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.x: B = None
        self.txt = txt

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

f = A("f")
i = B("i")
k = C("k")
h = D("h")
g = E("g")
e = F("e")
b = A("b")
l = C("l")
d = F("d")
j = A("j")

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.t: D = None
        self.x: B = None
        self.txt = txt

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

f = A("f")
i = B("i")
k = C("k")
h = D("h")
g = E("g")
e = F("e")
b = A("b")
l = C("l")
d = F("d")
j = A("j")

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