class A:
    def __init__(self, txt: str):
        self.t: G = None
        self.v: B = None
        self.q: J = None
        self.txt = txt

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

class C:
    def __init__(self, txt: str):
        self.w: F = None
        self.x: E = None
        self.z: G = None
        self.r: F = None
        self.y: H = None
        self.p: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: J = None
        self.y: I = None
        self.r: E = None
        self.u: H = None
        self.q: C = None
        self.s: F = None
        self.p: A = None
        self.t: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: J = None
        self.o: D = None
        self.x: C = None
        self.q: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: D = None
        self.x: E = None
        self.s: J = None
        self.v: D = None
        self.t: D = None
        self.u: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.q: E = None
        self.v: D = None
        self.w: A = None
        self.y: F = None
        self.o: G = None
        self.x: J = None
        self.z: F = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.q: H = None
        self.x: D = None
        self.r: I = None
        self.u: G = None
        self.z: D = None
        self.p: I = None
        self.y: E = None
        self.txt = txt

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

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

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

class C:
    def __init__(self, txt: str):
        self.w: F = None
        self.x: E = None
        self.z: G = None
        self.r: F = None
        self.y: H = None
        self.p: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: J = None
        self.y: I = None
        self.r: E = None
        self.u: H = None
        self.q: C = None
        self.s: F = None
        self.p: A = None
        self.t: H = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.z: J = None
        self.o: D = None
        self.x: C = None
        self.q: I = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.w: D = None
        self.x: E = None
        self.s: J = None
        self.v: D = None
        self.t: D = None
        self.u: B = None
        self.txt = txt

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

class H:
    def __init__(self, txt: str):
        self.q: E = None
        self.v: D = None
        self.w: A = None
        self.y: F = None
        self.o: G = None
        self.x: J = None
        self.z: F = None
        self.txt = txt

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

class J:
    def __init__(self, txt: str):
        self.q: H = None
        self.x: D = None
        self.r: I = None
        self.u: G = None
        self.z: D = None
        self.p: I = None
        self.y: E = None
        self.txt = txt

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

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