📅  最后修改于: 2022-03-11 14:45:37.657000             🧑  作者: Mango
def missingCharacters(s):
# Write your code here
checkk='0123456789abcdefghijklmnopqrstuvwxyz'
res=''
for letter in checkk:
if letter not in s:
res+=letter
return res