words = ["hello", "hall", "hello world"]
def few_letters(words):
    few_letters = len(words[0])
    for word in (range(len(words) - 1)):
        if few_letters <= len(words[word + 1]):
            passelse:
            few_letters = len(words[word + 1])
    return(few_letters)
def zipp(words):
        a = list()
        l = list()
        for i in range(few_letters(words)):
            for j in range(len(words)):
                l.append(words[j][i])
        x = 0for j in range(few_letters(words)):
            a.append([])
        for i in range(len(l)):
            if len(a[x]) == 3:
                x += 1
                a[x].append(l[i])
            else:
                a[x].append(l[i])
        return(a)
def common_prefix(words):
    a=zipp(words)
    tmp=""for i in a :
        if len(set(i)) != 1:
            breakelse:
            tmp+=i[0]
    print(tmp)
common_prefix(words)
##output : h