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

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

class C:
    def __init__(self, txt: str):
        self.x: D = None
        self.u: B = None
        self.v: D = None
        self.y: E = None
        self.w: D = None
        self.t: A = None
        self.r: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: B = None
        self.z: G = None
        self.q: G = None
        self.t: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: F = None
        self.r: A = None
        self.y: C = None
        self.v: E = None
        self.z: G = None
        self.o: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.s: A = None
        self.p: E = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.x: D = None
        self.u: B = None
        self.v: D = None
        self.y: E = None
        self.w: D = None
        self.t: A = None
        self.r: B = None
        self.txt = txt

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

class E:
    def __init__(self, txt: str):
        self.o: B = None
        self.z: G = None
        self.q: G = None
        self.t: C = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.q: F = None
        self.r: A = None
        self.y: C = None
        self.v: E = None
        self.z: G = None
        self.o: B = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.u: E = None
        self.s: A = None
        self.p: E = None
        self.txt = txt

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

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