Write definitions for the following two functions:
<OL>
<LI> sumN(n) returns the sum of the first n natural numbers.
<LI> sumNCubes(n) returns the sum of the cubes of the first n natural
numbers.
</OL>

Then test these functions with the following program.
<PRE>
<CODE>
def main():
    print( sumN(5), sumNCubes(5) )

main()
</CODE>
</PRE>