import sys

def f(s,n):
    ans=n;a=set(s)
    for i in a:
        if i=='0':continue
        for j in a:
            if i==j:continue
            else:
                t=i+j+j;b=''
                for k in s:
                    if t and k==t[0]:t=t[1:]
                    else:b+=k
                if not t:ans=max(ans,f(b,n+int(i+j+j)))
    return ans

print(f(input(),0))