def f(s,u,c):
 m=c
 for i in range(len(s)):
  for j in range(i+1,len(s)):
   for k in range(j+1,len(s)):
    if s[i]!='0' and s[j]==s[k]and s[i]!=s[j]:
     if not(u[i]or u[j]or u[k]):
      u[i]=u[j]=u[k]=True;m=max(m,f(s,u,c+int(s[i]+s[j]+s[k])));u[i]=u[j]=u[k]=False
 return m
s=input()
u=[False]*len(s)
print(f(s,u,0))