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

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

class C:
    def __init__(self, txt: str):
        self.o: A = None
        self.s: C = None
        self.x: E = None
        self.q: F = None
        self.z: A = None
        self.p: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.w: C = None
        self.y: F = None
        self.v: A = None
        self.u: C = None
        self.o: C = None
        self.q: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: B = None
        self.w: B = None
        self.r: E = None
        self.u: A = None
        self.txt = txt

c = A("c")
i = B("i")
g = C("g")
n = D("n")
a = E("a")
l = F("l")
e = C("e")
f = B("f")

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

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

class C:
    def __init__(self, txt: str):
        self.o: A = None
        self.s: C = None
        self.x: E = None
        self.q: F = None
        self.z: A = None
        self.p: A = None
        self.txt = txt

class D:
    def __init__(self, txt: str):
        self.v: F = None
        self.txt = txt

class E:
    def __init__(self, txt: str):
        self.w: C = None
        self.y: F = None
        self.v: A = None
        self.u: C = None
        self.o: C = None
        self.q: D = None
        self.txt = txt

class F:
    def __init__(self, txt: str):
        self.t: B = None
        self.w: B = None
        self.r: E = None
        self.u: A = None
        self.txt = txt

c = A("c")
i = B("i")
g = C("g")
n = D("n")
a = E("a")
l = F("l")
e = C("e")
f = B("f")

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