n = [*input()]
L = len(n)
s = [int("".join(n))]
for i in range(L):
    for j in range(i+1,L):
        n[i],n[j] = n[j],n[i]
        s.append(int("".join(n)))
        n[i],n[j] = n[j],n[i]
print(max(s))