N = raw_input()
a,b= list(N),list(N)
a.sort()
a.reverse()
for i in range(len(N)):
	if a[i] != b[i]:
		#b[i] = a[i]
		j = i + 1
		maxIndex = i
		while(j < len(N)):
			if b[maxIndex] <= b[j]:
				maxIndex = j
			j+=1
		b[maxIndex],b[i],= b[i],a[i]
		break
print ''.join(b)