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

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

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

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

class E:
    def __init__(self, txt: str):
        self.w: G = None
        self.z: B = None
        self.y: C = None
        self.s: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: A = None
        self.q: B = None
        self.txt = txt

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

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

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

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

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

class E:
    def __init__(self, txt: str):
        self.w: G = None
        self.z: B = None
        self.y: C = None
        self.s: F = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.p: A = None
        self.q: B = None
        self.txt = txt

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

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