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

class B:
    def __init__(self, txt: str):
        self.y: C = None
        self.z: F = None
        self.v: A = None
        self.x: C = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: B = None
        self.y: G = None
        self.s: F = None
        self.q: B = None
        self.w: F = None
        self.x: C = None
        self.p: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: E = None
        self.w: D = None
        self.o: E = None
        self.txt = txt

g = A("g")
j = B("j")
n = C("n")
c = D("c")
f = E("f")
h = F("h")
d = G("d")
m = G("m")
l = C("l")

g.z = j
g.v = h
j.y = n
j.z = h
j.v = g
j.x = l
n.z = j
n.o = d
n.t = d
n.s = f
n.u = l
n.x = h
n.w = c
c.s = l
f.o = j
f.q = j
f.y = m
f.s = h
f.w = h
f.x = l
f.p = g
h.q = l
h.s = n
d.z = f
d.o = f
d.w = c
m.z = f
m.o = f
m.w = c
l.z = j
l.o = m
l.s = f
l.u = n
l.x = h
l.t = d
l.w = c
assert c.s.z.v.z.v.z.z.txt == "
class A:
    def __init__(self, txt: str):
        self.z: B = None
        self.v: F = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: C = None
        self.z: F = None
        self.v: A = None
        self.x: C = None
        self.txt = txt

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

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

class E:
    def __init__(self, txt: str):
        self.o: B = None
        self.y: G = None
        self.s: F = None
        self.q: B = None
        self.w: F = None
        self.x: C = None
        self.p: A = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: E = None
        self.w: D = None
        self.o: E = None
        self.txt = txt

g = A("g")
j = B("j")
n = C("n")
c = D("c")
f = E("f")
h = F("h")
d = G("d")
m = G("m")
l = C("l")

g.z = j
g.v = h
j.y = n
j.z = h
j.v = g
j.x = l
n.z = j
n.o = d
n.t = d
n.s = f
n.u = l
n.x = h
n.w = c
c.s = l
f.o = j
f.q = j
f.y = m
f.s = h
f.w = h
f.x = l
f.p = g
h.q = l
h.s = n
d.z = f
d.o = f
d.w = c
m.z = f
m.o = f
m.w = c
l.z = j
l.o = m
l.s = f
l.u = n
l.x = h
l.t = d
l.w = c
assert c.s.z.v.z.v.z.z.txt == "h"