str = "aaaa12312"
strlist = [];
a = -1
while a<len(str)-1:
a=a+1
print str[a].isdigit()
if str[a].isdigit():
strlist.append('*')
else:
strlist.append(str[a])
result = ''.join(strlist)
print(result)
c3RyID0gImFhYWExMjMxMiIKc3RybGlzdCA9IFtdOwphID0gLTEKCndoaWxlIGE8bGVuKHN0ciktMToKICAgIGE9YSsxCiAgICBwcmludCBzdHJbYV0uaXNkaWdpdCgpCiAgICAKICAgIGlmIHN0clthXS5pc2RpZ2l0KCk6CiAgICAgICAgc3RybGlzdC5hcHBlbmQoJyonKQogICAgZWxzZToKICAgICAgICBzdHJsaXN0LmFwcGVuZChzdHJbYV0pCiAgICAKcmVzdWx0ID0gJycuam9pbihzdHJsaXN0KQoKcHJpbnQocmVzdWx0KQ==