N = list(input())
max = 0
num_max = 0
for i in range(len(N)-1,-1,-1):
    if max < int(N[i]):
        max = int(N[i])
        num_max = i
        
irekae_num = 0
for i in range(len(N)):
    if N[num_max] != N[i]:
        irekae_num = i
        break
N[irekae_num],N[num_max] = N[num_max],N[irekae_num]
print("".join(N))