N=input()

MAX=[0]
def dfs(score,N):
    #print(score,N)
    MAX[0]=max(MAX[0],score)

    for i in range(len(N)):
        for j in range(i+1,len(N)):
            for k in range(j+1,len(N)):
                if N[j]==N[k] and N[i]!=N[j]:
                    x=int(N[i])*100 + int(N[j])*11
                    k=N[:k]+N[k+1:]
                    l=k[:j]+k[j+1:]
                    m=l[:i]+l[i+1:]
                    dfs(score+x,m)

dfs(0,N)
print(MAX[0])