class A:
    def __init__(self, txt: str):
        self.s: G = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.q: C = None
        self.z: C = None
        self.r: I = None
        self.t: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: I = None
        self.q: B = None
        self.s: E = None
        self.w: I = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: C = None
        self.v: A = None
        self.y: H = None
        self.z: I = None
        self.s: H = None
        self.x: G = None
        self.r: C = None
        self.t: I = None
        self.u: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.p: J = None
        self.s: C = None
        self.t: F = None
        self.q: I = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.q: D = None
        self.p: G = None
        self.w: A = None
        self.x: F = None
        self.y: A = None
        self.u: F = None
        self.txt = txt

d = A("d")
l = B("l")
i = C("i")
g = D("g")
e = E("e")
f = F("f")
j = G("j")
c = H("c")
b = I("b")
n = J("n")

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

class B:
    def __init__(self, txt: str):
        self.q: C = None
        self.z: C = None
        self.r: I = None
        self.t: E = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.r: I = None
        self.q: B = None
        self.s: E = None
        self.w: I = None
        self.txt = txt

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

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

class F:
    def __init__(self, txt: str):
        self.o: C = None
        self.v: A = None
        self.y: H = None
        self.z: I = None
        self.s: H = None
        self.x: G = None
        self.r: C = None
        self.t: I = None
        self.u: H = None
        self.txt = txt

class G:
    def __init__(self, txt: str):
        self.p: J = None
        self.s: C = None
        self.t: F = None
        self.q: I = None
        self.txt = txt

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

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

class J:
    def __init__(self, txt: str):
        self.q: D = None
        self.p: G = None
        self.w: A = None
        self.x: F = None
        self.y: A = None
        self.u: F = None
        self.txt = txt

d = A("d")
l = B("l")
i = C("i")
g = D("g")
e = E("e")
f = F("f")
j = G("j")
c = H("c")
b = I("b")
n = J("n")

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