N = list(map(int, list(input())))

M, M_i = 0, -1
for i, n in enumerate(N):
    if n >= M:
        M = n
        M_i = i


for i, n in enumerate(N):
    if n < M and M_i > i:
        N[i] = M
        N[M_i] = n
        break

print(''.join(map(str, N)))