#yuki_437

def f(s,n):
 res=n
 for i in xrange(len(s)):
  for j in xrange(i+1,len(s)):
   for k in xrange(j+1,len(s)):
    if s[i]!='0' and s[i]!=s[j] and s[j]==s[k]:
     res=max(res,f(s[:i]+s[i+1:j]+s[j+1:k],n+int(s[i]+s[j]+s[k])))
 return res

print f(raw_input(),0)