from itertools import combinations
N = list(input())
ansl = [int(''.join(N))]
for pat in combinations([i for i in range(len(N))], 2):
    # (0, 3)
    i, j = pat
    N[i], N[j] = N[j], N[i]
    sub = int(''.join(N))
    ansl.append(sub)
    N[i], N[j] = N[j], N[i]
print(max(ansl))