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

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

class C:
    def __init__(self, txt: str):
        self.r: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: F = None
        self.x: G = None
        self.t: F = None
        self.v: C = None
        self.r: G = None
        self.y: C = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: F = None
        self.r: A = None
        self.p: F = None
        self.t: C = None
        self.x: D = None
        self.q: E = None
        self.w: F = None
        self.txt = txt

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

b.v = m
b.p = d
b.t = d
b.o = d
b.u = f
n.r = l
n.y = d
c.r = e
l.o = d
l.t = d
l.x = m
l.r = m
l.v = c
l.y = c
e.s = m
e.v = m
e.u = c
e.y = d
e.w = l
e.p = l
e.x = l
d.u = n
d.s = b
m.u = d
m.p = d
m.w = d
m.r = b
m.t = c
m.x = l
m.q = e
a.s = m
a.v = m
a.u = c
a.y = d
a.w = l
a.p = l
a.x = l
f.s = m
f.v = m
f.u = c
f.y = d
f.w = l
f.p = l
f.x = l
assert l.o.u.y.u.r.y.r.y.s.txt == "
class A:
    def __init__(self, txt: str):
        self.v: G = None
        self.p: F = None
        self.u: E = None
        self.t: F = None
        self.o: F = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.r: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: F = None
        self.x: G = None
        self.t: F = None
        self.v: C = None
        self.r: G = None
        self.y: C = None
        self.txt = txt

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

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

class G:
    def __init__(self, txt: str):
        self.u: F = None
        self.r: A = None
        self.p: F = None
        self.t: C = None
        self.x: D = None
        self.q: E = None
        self.w: F = None
        self.txt = txt

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

b.v = m
b.p = d
b.t = d
b.o = d
b.u = f
n.r = l
n.y = d
c.r = e
l.o = d
l.t = d
l.x = m
l.r = m
l.v = c
l.y = c
e.s = m
e.v = m
e.u = c
e.y = d
e.w = l
e.p = l
e.x = l
d.u = n
d.s = b
m.u = d
m.p = d
m.w = d
m.r = b
m.t = c
m.x = l
m.q = e
a.s = m
a.v = m
a.u = c
a.y = d
a.w = l
a.p = l
a.x = l
f.s = m
f.v = m
f.u = c
f.y = d
f.w = l
f.p = l
f.x = l
assert l.o.u.y.u.r.y.r.y.s.txt == "b"