print set()

# sets
s = set()
print set(s)

# lists
l = [1,2,3,4]
print set([])
print set([1,2,3,4])
print set(l)

# tuples
t = (1,2,3,4)
print set(())
print set((1,2,3,4))
print set(t)

# dictionaries
d = {1:2,3:4}
print set({})
print set(d)
print set(d.keys())
print set(d.values())