python3

s = list(input().replace(' ', ''))
s[::2] = sorted(s[::2])
s[1::2] = sorted(s[1::2])
res = []
for i in s:
    try:
        res.append(hex(int(bin(int(i, 16))[2:].rjust(4, '0')[::-1], 2))[2:].upper())
    except:
        res.append(i)
print(''.join(res))