x,li,small,maxx,c = input(),list(),0,0,1
for i in range(len(x)):
               li.append(int(x[i]))
for i in range(len(li)-1,-1,-1):
    if(i==0):
        print("No Number Possible")
        c=0
        break
    if(li[i]>li[i-1]):
        small = i-1
        maxx = i
        break
for i in range(small+1,len(li)):
    if(li[i]>li[small] and li[i]<li[maxx]):
        maxx = i
li[small],li[maxx]=li[maxx],li[small]
li = li[:small+1] + sorted(li[small+1:])
if(c):
    for i in range(len(li)):
        print(li[i],end = '' )