seq = list(input())
seq = list(map(int,seq))
N = len(seq)
max_sum = 0

def calc(i,lst,sum_cww):
    global max_sum
    if i<0:
        if sum_cww>max_sum:
            max_sum=sum_cww
        return
    x = seq[i]
    lst[x]+=1
    calc(i-1,lst[:],sum_cww)
    if x==0:
        return
    for j in range(10):
        if lst[j]>1 and j!=x:
            tmp = lst[:]
            tmp[x] -= 1
            tmp[j] -= 2
            calc(i-1,tmp[:],sum_cww+x*100+j*11)

calc(N-1,[0]*10,0)
print(max_sum)