class A:
    def __init__(self, txt: str):
        self.o: D = None
        self.s: F = None
        self.t: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.q: F = None
        self.x: F = None
        self.t: F = None
        self.s: E = None
        self.u: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.r: C = None
        self.z: B = None
        self.s: C = None
        self.q: F = None
        self.u: C = None
        self.p: D = None
        self.txt = txt

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

f = A("f")
b = B("b")
l = C("l")
m = D("m")
a = E("a")
n = F("n")
k = A("k")
e = E("e")

f.o = m
f.t = m
f.s = n
b.r = m
l.q = n
l.x = n
l.t = n
l.s = a
l.u = m
m.s = b
m.o = a
m.u = e
m.v = e
m.p = k
m.q = l
a.r = l
a.s = l
a.u = l
a.z = b
a.q = n
a.p = m
n.v = f
n.s = l
n.q = l
n.u = l
k.o = m
k.t = m
k.s = n
e.r = l
e.s = l
e.u = l
e.z = b
e.q = n
e.p = m
assert k.o.p.s.v.s.u.u.txt == "
class A:
    def __init__(self, txt: str):
        self.o: D = None
        self.s: F = None
        self.t: D = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.q: F = None
        self.x: F = None
        self.t: F = None
        self.s: E = None
        self.u: D = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.r: C = None
        self.z: B = None
        self.s: C = None
        self.q: F = None
        self.u: C = None
        self.p: D = None
        self.txt = txt

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

f = A("f")
b = B("b")
l = C("l")
m = D("m")
a = E("a")
n = F("n")
k = A("k")
e = E("e")

f.o = m
f.t = m
f.s = n
b.r = m
l.q = n
l.x = n
l.t = n
l.s = a
l.u = m
m.s = b
m.o = a
m.u = e
m.v = e
m.p = k
m.q = l
a.r = l
a.s = l
a.u = l
a.z = b
a.q = n
a.p = m
n.v = f
n.s = l
n.q = l
n.u = l
k.o = m
k.t = m
k.s = n
e.r = l
e.s = l
e.u = l
e.z = b
e.q = n
e.p = m
assert k.o.p.s.v.s.u.u.txt == "m"