n=sorted(map(int,[*input()]))[::-1]
if len(set(n))==1:
    print(-1)
elif len(set(n))==2:
    if n[1]==0:
        print(-1)
    else:
        print(n[1],n[1],sep='')
else:
    for i in range(2,len(n)):
        if n[1]>n[i]:
            n[1],n[i]=n[i],n[1]
            print(*n,sep='')
            break
    else:
        print(-1)