f=->s{r=0;n=s.size;n.times{|i|(i+1..n-1).map{|j|(j+1..n-1).map{|k|x=(s[i]+s[j]+s[k]).to_i;(t=s.dup;s[i]=s[j]=s[k]='';r=[r,x+f[s]].max;s=t)if s[i]>?0&&s[j]!=s[i]&&s[j]==s[k]}}};r}
p f[gets.chop]