class A:
    def __init__(self, txt: str):
        self.y: C = None
        self.s: I = None
        self.q: E = None
        self.t: C = None
        self.o: F = None
        self.w: D = None
        self.u: C = None
        self.r: C = None
        self.x: B = None
        self.txt = txt

class B:
    def __init__(self, txt: str):
        self.p: I = None
        self.t: C = None
        self.u: I = None
        self.s: I = None
        self.z: D = None
        self.x: E = None
        self.r: F = None
        self.q: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: B = None
        self.q: H = None
        self.x: I = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.t: B = None
        self.w: C = None
        self.o: A = None
        self.y: I = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.z: D = None
        self.s: B = None
        self.y: B = None
        self.txt = txt

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

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

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

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

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

class B:
    def __init__(self, txt: str):
        self.p: I = None
        self.t: C = None
        self.u: I = None
        self.s: I = None
        self.z: D = None
        self.x: E = None
        self.r: F = None
        self.q: F = None
        self.txt = txt

class C:
    def __init__(self, txt: str):
        self.z: B = None
        self.q: H = None
        self.x: I = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.t: B = None
        self.w: C = None
        self.o: A = None
        self.y: I = None
        self.txt = txt

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

class F:
    def __init__(self, txt: str):
        self.z: D = None
        self.s: B = None
        self.y: B = None
        self.txt = txt

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

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

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

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

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