class A:
    def __init__(self, txt: str):
        self.q: D = None
        self.p: I = None
        self.t: C = None
        self.y: E = None
        self.u: E = None
        self.z: I = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.r: I = None
        self.t: D = None
        self.p: C = None
        self.u: I = None
        self.v: I = None
        self.s: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: D = None
        self.r: I = None
        self.y: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: G = None
        self.p: H = None
        self.y: I = None
        self.x: I = None
        self.z: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: H = None
        self.t: C = None
        self.p: I = None
        self.o: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.v: E = None
        self.x: B = None
        self.p: H = None
        self.o: I = None
        self.t: B = None
        self.r: E = None
        self.y: G = None
        self.w: A = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.r: E = None
        self.p: C = None
        self.o: B = None
        self.t: I = None
        self.v: F = None
        self.u: C = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: B = None
        self.t: C = None
        self.r: A = None
        self.v: D = None
        self.o: I = None
        self.x: C = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: F = None
        self.txt = txt

i = A("i")
l = B("l")
b = C("b")
n = D("n")
k = E("k")
a = F("a")
g = G("g")
j = H("j")
c = I("c")

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

class B:
    def __init__(self, txt: str):
        self.r: I = None
        self.t: D = None
        self.p: C = None
        self.u: I = None
        self.v: I = None
        self.s: D = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: D = None
        self.r: I = None
        self.y: G = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.q: G = None
        self.p: H = None
        self.y: I = None
        self.x: I = None
        self.z: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.r: H = None
        self.t: C = None
        self.p: I = None
        self.o: F = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.v: E = None
        self.x: B = None
        self.p: H = None
        self.o: I = None
        self.t: B = None
        self.r: E = None
        self.y: G = None
        self.w: A = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.r: E = None
        self.p: C = None
        self.o: B = None
        self.t: I = None
        self.v: F = None
        self.u: C = None
        self.w: H = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.q: B = None
        self.t: C = None
        self.r: A = None
        self.v: D = None
        self.o: I = None
        self.x: C = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.y: F = None
        self.txt = txt

i = A("i")
l = B("l")
b = C("b")
n = D("n")
k = E("k")
a = F("a")
g = G("g")
j = H("j")
c = I("c")

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