print "sum of two is", sum
If you need to keep the python 3 syntax of using parentheses, other solutions are:
* use str to convert the variable into a string, and + to concatenate the two strings
print("sum of two is" + " "+str(sum))
* use join, str, and a list comprehension to combine the elements
print(" ".join([str(x) for x in ("sum of two is", sum)]))
I hope that helps.