题解 | #字符串合并处理#

    try:
        s1, s2 = input().split()
        s = s1 + s2
        s_even = sorted(s[::2])
        s_odd = sorted(s[1::2])
        ss = ''
        for i in range(len(s)):
            if i % 2 == 0:
                ss += s_even[i // 2]
            else:
                ss += s_odd[(i - 1) // 2]
        res = []
        for i in ss:
            if '0' <= i <= '9' or 'a' <= i <= 'f' or 'A' <= i <= 'F':
                b = bin(int(i, 16))[2:]
                b = '0' * (4 - len(b)) + str(b)
                h = hex(int(b[::-1], 2))[2:]
                if str(h).islower():
                    h = h.upper()
                res.append(h)
            else:
                res.append(i)
        print(''.join(str(i) for i in res))
    except:
        break