m=list(input())
ans=int(''.join(m))
for i in range(len(m)-1):
    for j in range(i+1,len(m)):
        m[i],m[j] = m[j], m[i]
        t=int(''.join(m))
        ans=max(ans,t)
        m[i],m[j] = m[j], m[i]
        
print(ans)