Any prime close to max value of int will cause this solution to timeout.

This solution will not work properly in case of int overflow.

I am disappointed with this website ... it teaches to write inefficient and incorrect code

• returning negative number instead of zero is WRONG
• int can overflow to positive value as well

This solution is too slow anyway (if we are talking about performance) to bother about such minor optimization at all.

Will this solution still work for tests where words are separated by more than one space?