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

class B:
    def __init__(self, txt: str):
        self.v: F = None
        self.t: H = None
        self.u: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: G = None
        self.r: I = None
        self.s: F = None
        self.t: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: G = None
        self.x: I = None
        self.p: A = None
        self.o: G = None
        self.s: G = None
        self.y: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: I = None
        self.s: F = None
        self.q: I = None
        self.p: D = None
        self.r: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: G = None
        self.p: G = None
        self.v: D = None
        self.s: I = None
        self.r: G = None
        self.w: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.w: D = None
        self.o: B = None
        self.s: B = None
        self.v: C = None
        self.t: D = None
        self.y: I = None
        self.u: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.t: A = None
        self.w: D = None
        self.z: C = None
        self.x: A = None
        self.s: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: E = None
        self.txt = txt

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

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

class B:
    def __init__(self, txt: str):
        self.v: F = None
        self.t: H = None
        self.u: G = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.o: G = None
        self.r: I = None
        self.s: F = None
        self.t: F = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.u: G = None
        self.x: I = None
        self.p: A = None
        self.o: G = None
        self.s: G = None
        self.y: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.y: I = None
        self.s: F = None
        self.q: I = None
        self.p: D = None
        self.r: G = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.u: G = None
        self.p: G = None
        self.v: D = None
        self.s: I = None
        self.r: G = None
        self.w: G = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.w: D = None
        self.o: B = None
        self.s: B = None
        self.v: C = None
        self.t: D = None
        self.y: I = None
        self.u: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.t: A = None
        self.w: D = None
        self.z: C = None
        self.x: A = None
        self.s: I = None
        self.txt = txt

class I:
    def __init__(self, txt: str):
        self.v: E = None
        self.txt = txt

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

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