l=list(map(int,list(input())))
s=sorted(l)[::-1]
for i in range(len(l)):
	if l[i]!=s[i]:
		t=max([j for j, x in enumerate(l) if x==max(l[i:])])
		l[i],l[t]=l[t],l[i]
		break
print(*l,sep='')