Powerful digit sum

A googol (\( 10100 \)) is a massive number: one followed by one-hundred zeros; \( 100100 \) is almost unimaginably large: one followed by two-hundred zeros. Despite their size, the sum of the digits in each number is only \( 1 \).

Considering natural numbers of the form, ab, where a, b \( <100 \), what is the maximum digital sum?