Read an arbitrarily long sequence of positive numbers from the user, until -1 is entered. At that point, print ”Yes” if the numbers were consecutive and increasing and ”No” otherwise. Sequences ”1,2,3,4,-1” and ”5,6,7,8,9,10,11,-1” should output ”Yes”, but ”2,3,5,6,7,-1”, ”10,9,8,7,-1”, and ”1,1,2,3,4,5,-1” should output ”No”.