String Without AAA or BBB

Given two integers a and b, return any string s such that:

s has length a + b and contains exactly a 'a' letters, and exactly b 'b' letters.
The substring 'aaa' does not occur in s.
The substring 'bbb' does not occur in s.

Example 1

Inputa = 1, b = 2

Output"abb"

"abb", "bab", and "bba" are all correct answers.

Example 2

Inputa = 4, b = 1

Output"aabaa"

The string has exactly four 'a' letters and one 'b' letter without containing 'aaa' or 'bbb'.

Constraints