class Solution:
    def longestCommonPrefix(self, strs):
        """
        :type strs: List[str]
        :rtype: str
        """
        if(len(strs)==0):
            return ""
        elif(len(strs)==1):
            return strs[0]
        else:
            s=sorted(strs,key=lambda x:len(x) ) 
            print(s)
        f1=s[0]
        re=''
        for i,j in enumerate(f1):
            l=[]
            for k in s[1:]:
                l.append(k[i]==j)
            if all(l):
                re=re+j
            else:
                break  
        return re