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;t[i]=t[j]=t[k]='';r=[r,x+f[t]].max)if s[i]>?0&&s[j]!=s[i]&&s[j]==s[k]}}};r};p f[gets]