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

class B:
    def __init__(self, txt: str):
        self.r: C = None
        self.t: G = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.w: D = None
        self.x: F = None
        self.txt = txt

f = A("f")
c = B("c")
b = C("b")
h = D("h")
i = E("i")
m = F("m")
a = G("a")
k = E("k")
l = B("l")
j = D("j")

f.x = b
f.z = b
f.u = m
f.r = j
f.y = a
f.t = a
c.r = b
c.t = a
b.y = k
h.x = m
h.v = m
h.p = m
h.w = j
h.y = a
h.q = b
h.u = i
i.q = j
i.s = b
m.r = f
m.s = c
m.q = h
a.w = h
a.x = m
k.q = h
k.s = b
l.r = b
l.t = a
j.x = m
j.v = m
j.p = m
j.w = h
j.y = a
j.q = b
j.u = i
assert i.q.u.q.v.r.u.s.r.txt == "
class A:
    def __init__(self, txt: str):
        self.x: C = None
        self.u: F = None
        self.r: D = None
        self.y: G = None
        self.z: C = None
        self.t: G = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: C = None
        self.t: G = None
        self.txt = txt

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

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

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

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

class G:
    def __init__(self, txt: str):
        self.w: D = None
        self.x: F = None
        self.txt = txt

f = A("f")
c = B("c")
b = C("b")
h = D("h")
i = E("i")
m = F("m")
a = G("a")
k = E("k")
l = B("l")
j = D("j")

f.x = b
f.z = b
f.u = m
f.r = j
f.y = a
f.t = a
c.r = b
c.t = a
b.y = k
h.x = m
h.v = m
h.p = m
h.w = j
h.y = a
h.q = b
h.u = i
i.q = j
i.s = b
m.r = f
m.s = c
m.q = h
a.w = h
a.x = m
k.q = h
k.s = b
l.r = b
l.t = a
j.x = m
j.v = m
j.p = m
j.w = h
j.y = a
j.q = b
j.u = i
assert i.q.u.q.v.r.u.s.r.txt == "b"