Py- Longest string in alphabetical order

#Longest string in alphabetical order-contains error
s = "azcbobobegghijkkklakl"
ls = ""
for i in range(0, len(s)-1):
    temp = ""
    ss = ""
    ks=''
    j = 2
    while j < len(s):
        ss = s[i:i+j]
        temp = sorted(ss)
        str1 = ''.join(temp)
        j += 1
        if str1 == ss:
            ks = ss
        else:
            break
    if len(ks) > len(ls):
        ls = ks
print("The Longest substring in alphabetical order is "+ls)