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

class B:
    def __init__(self, txt: str):
        self.t: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.p: B = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: E = None
        self.t: A = None
        self.z: E = None
        self.y: E = None
        self.u: C = None
        self.v: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.q: F = None
        self.y: D = None
        self.s: D = None
        self.o: A = None
        self.t: A = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.t: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: B = None
        self.p: B = None
        self.v: B = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.o: E = None
        self.t: A = None
        self.z: E = None
        self.y: E = None
        self.u: C = None
        self.v: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.q: F = None
        self.y: D = None
        self.s: D = None
        self.o: A = None
        self.t: A = None
        self.txt = txt

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

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

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