N = list(raw_input())[::-1]
l = len(N)
for i in xrange(l):
	m = max(N[:l-i])
	idx = N.index(m)
	if N[l-1-i] != m:
		N[idx],N[l-1-i] = N[l-1-i],N[idx]
		break
print "".join(N[::-1])