N = raw_input()
mx = max(N)
index = N.index(mx)

mx = int(N)
for i in xrange(len(N)):
    for j in xrange(i + 1, len(N)):
        A = list(N)
        tmp = A[i]
        A[i] = N[j]
        A[j] = tmp
        mx = max(int("".join(A)), mx)

print mx