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

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

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

class D:
    def __init__(self, txt: str):
        self.z: H = None
        self.s: J = None
        self.x: A = None
        self.o: E = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.r: B = None
        self.t: D = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.s: C = None
        self.q: I = None
        self.r: C = None
        self.y: D = None
        self.w: A = None
        self.u: I = None
        self.o: G = None
        self.txt = txt

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

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

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

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

class D:
    def __init__(self, txt: str):
        self.z: H = None
        self.s: J = None
        self.x: A = None
        self.o: E = None
        self.txt = txt

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

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

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

class H:
    def __init__(self, txt: str):
        self.r: B = None
        self.t: D = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.s: C = None
        self.q: I = None
        self.r: C = None
        self.y: D = None
        self.w: A = None
        self.u: I = None
        self.o: G = None
        self.txt = txt

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

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