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

class B:
    def __init__(self, txt: str):
        self.t: C = None
        self.o: A = None
        self.z: D = None
        self.p: C = None
        self.y: D = None
        self.w: A = None
        self.s: A = None
        self.txt = txt

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

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

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

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

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

k = A("k")
j = B("j")
i = C("i")
b = D("b")
c = E("c")
n = F("n")
g = G("g")
m = D("m")
d = C("d")

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

class B:
    def __init__(self, txt: str):
        self.t: C = None
        self.o: A = None
        self.z: D = None
        self.p: C = None
        self.y: D = None
        self.w: A = None
        self.s: A = None
        self.txt = txt

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

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

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

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

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

k = A("k")
j = B("j")
i = C("i")
b = D("b")
c = E("c")
n = F("n")
g = G("g")
m = D("m")
d = C("d")

k.z = c
k.u = c
j.t = i
j.p = i
j.o = k
j.w = k
j.s = k
j.z = m
j.y = m
i.x = j
i.v = j
i.p = d
i.t = n
i.z = g
i.w = g
i.y = k
b.t = c
b.q = n
b.v = m
b.p = j
b.x = g
c.r = g
c.u = g
c.s = k
c.w = j
n.r = m
g.p = j
g.s = b
g.u = i
m.t = c
m.q = n
m.v = b
m.p = j
m.x = g
d.x = j
d.v = j
d.p = i
d.t = n
d.z = g
d.w = g
d.y = k
assert c.w.o.u.txt == "c"