s=list(map(int,list(input())))
s=sorted(s)[::-1]
l=[x for x in s]
x=-1
for i in range(1,len(s)):
	l[-i],l[-i-1]=l[-i-1],l[-i]
	if l!=s and l[0]!=0: 
		x=''.join(map(str,l)); break
print(x)