Largest Merge of Two Strings

class Solution(object):
    def largestMerge(self, word1, word2):
        p1, p2 =0, 0
        merge=""
        
        while p1< len(word1) and p2< len(word2):
            if word1[p1:] > word2[p2:]:
                merge+=word1[p1]
                p1+=1
            else:
                merge+=word2[p2]
                p2+=1
        #if one of the word is empty, so we concatenate the left char
        merge+=word1[p1:]+word2[p2:]

        return merge


# why not word1[p1] or word2[p2]? this is to determine which char I have to choose when the char we are comparing are equal(if word1[p1]==word2[p2]) depending on the chars on the left e.g. if w1=adaa and w2= acaaaaa, I have to choose the a's of w1 since the left value of w1>w2 (daa> caaaaa or d>c).