x=list(input())
x.sort()
for i in range(1,len(x)):
	if x[i]!=x[0]:
		if i==len(x)-1 and x[i-1]=="0":
			continue
		x[i],x[i-1]=x[i-1],x[i]
		print("".join(x[::-1]))
		exit()
print("-1")