l = list(input())
ans_l = [0]
#print(l)

def cww(l, l1, ans):
    l1.reverse()
    for l1_i in l1:
        l.pop(l1_i)
    l1 = []

    for i in range(len(l)):
        #print(i,"iiiiiiiii")
        if l[i] == "0":
            continue
        for j in range(i + 1, len(l)):
            #print(j,"jjjjjjjjj")
            if l[j] == l[i]:
                continue
            for k in range(j + 1, len(l)):
                if l[j] == l[k]:
                    l1.append(i)
                    l1.append(j)
                    l1.append(k)
                    #print(l[i] + l[j] + l[k])
                    #print(l,l1)
                    if ans_l[-1] < ans + int(l[i] + l[j] + l[k]):
                        ans_l.append(ans + int(l[i] + l[j] + l[k]))
                    cww(l[:], l1, ans + int(l[i] + l[j] + l[k]))
                    l1 = []
    return 0

cww(l, [], 0)
print(ans_l[-1])