class A:
    def __init__(self, txt: str):
        self.q: G = None
        self.s: C = None
        self.y: G = None
        self.t: D = None
        self.z: C = None
        self.o: H = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.y: A = None
        self.r: I = None
        self.u: F = None
        self.z: I = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: H = None
        self.t: G = None
        self.u: G = None
        self.p: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: H = None
        self.x: E = None
        self.u: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: E = None
        self.r: B = None
        self.w: I = None
        self.v: D = None
        self.s: E = None
        self.t: C = None
        self.q: B = None
        self.p: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: G = None
        self.w: C = None
        self.txt = txt

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

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

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

class B:
    def __init__(self, txt: str):
        self.y: A = None
        self.r: I = None
        self.u: F = None
        self.z: I = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.w: H = None
        self.t: G = None
        self.u: G = None
        self.p: E = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.s: H = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.v: H = None
        self.x: E = None
        self.u: E = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.y: E = None
        self.r: B = None
        self.w: I = None
        self.v: D = None
        self.s: E = None
        self.t: C = None
        self.q: B = None
        self.p: E = None
        self.txt = txt

class H:
    def __init__(self, txt: str):
        self.y: G = None
        self.w: C = None
        self.txt = txt

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

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

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