Construct the recurrence and initial conditions. No uppercase letters.

An az is a string of lower case English letters which follows the rule that all the a's in the string must precede all the z's in the string. (There are 26 unique English letters) These strings are azzes: azo aazz alcatraz alabama puppies xyzzy induction amazon paparazzi These strings are not azzes: zoa azaz arizona zyzzyva zynga pizazz pizzeria Construct a recurrence and appropriate initial conditions for the number of azzes of length n, for n greaterthanorequalto 0