l = input()
s = sorted(l)[::-1]
if list(l) == s:
    print(''.join(l))
for i in range(len(l)):
    if l[i] != s[i]:
        x = l.rfind(s[i])
        l =list(l)
        l[x],l[i] = l[i],l[x]
        break
print(''.join(l))