from itertools import combinations
s=list(input())
n=len(s)
ans=''
for i in s:
    ans+=str(i)
ans=int(ans)
for com in combinations(range(n),2):
    x,y=com
    s[x],s[y]=s[y],s[x]
    tmp=''
    for i in s:
        tmp+=str(i)
    tmp=int(tmp)
    ans=max(ans,tmp)
    s[x],s[y]=s[y],s[x]
print(ans)