def to_int(ds):
    res = 0
    for d in ds:
        res *= 10
        res += d
    return res


def swap(ds, i, j):
    ds2 = ds[:]
    x = ds2[i]
    y = ds2[j]
    ds2[i] = y
    ds2[j] = x
    return ds2

ds = [int(x) for x in raw_input()]
L = len(ds)

ans = max([to_int(swap(ds, i, j))
           for i in range(L) for j in range(L)])
print(ans)