If a POS expression uses five input variables and has a sum within it that uses only three variables, how many rows in the POS expression's truth table have zeros as a result of that sum?

Apython programming question: assume s is a string of lower case characters. write a program that prints the number of times the string 'bob' occurs in s. for example, if s = 'azcbobobegghakl', then your program should print number of times bob occurs is: 2