#print(sorted('Ihave1nose2hands10fingers'))
#print('Ihave1nose2hands10fingers'.sort())

'''
while True:
    try:
        string=str(input())
        string1=sorted(string)
        #print(string1)
        print(''.join(string1))
    except:
        break'''

print(''.join(sorted(input())))  # 更简洁