class A:
    def __init__(self, txt: str):
        self.y: B = None
        self.u: E = None
        self.q: F = None
        self.z: I = None
        self.p: I = None
        self.x: G = None
        self.o: I = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.o: I = None
        self.u: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: I = None
        self.p: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.u: D = None
        self.p: D = None
        self.txt = txt

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

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

b.y = m
b.u = h
b.q = n
b.z = k
b.p = k
b.x = g
b.o = j
m.q = h
m.v = h
m.z = g
m.p = n
m.u = l
m.s = l
m.o = j
m.w = b
m.r = b
a.v = k
a.q = h
f.u = a
f.p = g
h.o = k
h.u = l
n.v = k
g.z = k
g.p = b
l.o = g
l.u = f
l.p = f
j.x = h
k.x = h
assert f.p.p.u.txt == "
class A:
    def __init__(self, txt: str):
        self.y: B = None
        self.u: E = None
        self.q: F = None
        self.z: I = None
        self.p: I = None
        self.x: G = None
        self.o: I = None
        self.txt = txt

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

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

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

class E:
    def __init__(self, txt: str):
        self.o: I = None
        self.u: H = None
        self.txt = txt

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

class G:
    def __init__(self, txt: str):
        self.z: I = None
        self.p: A = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.o: G = None
        self.u: D = None
        self.p: D = None
        self.txt = txt

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

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

b.y = m
b.u = h
b.q = n
b.z = k
b.p = k
b.x = g
b.o = j
m.q = h
m.v = h
m.z = g
m.p = n
m.u = l
m.s = l
m.o = j
m.w = b
m.r = b
a.v = k
a.q = h
f.u = a
f.p = g
h.o = k
h.u = l
n.v = k
g.z = k
g.p = b
l.o = g
l.u = f
l.p = f
j.x = h
k.x = h
assert f.p.p.u.txt == "h"