Given a rows x cols screen and a sentence represented by a list of non-empty words, find how many times the given sentence can be fitted on the screen.

class Solution:
    def wordsTyping(self, sentence: List[str], rows: int, cols: int) -> int:

        new_s = " ".join(sentence) + " "
        start = 0
        for i in xrange(rows):
            start += cols
            if new_s[start % len(new_s)] == " ":
                start += 1
            else:
                while start > 0 and new_s[(start - 1) % len(new_s)] != " ":
                    start -= 1
        return start / len(new_s)