题解 | #字符串合并处理#

while 1:
    try:
        s0 = input().split()
        s1 = s0[0]
        s2 = s0[1]

        s = s1 + s2
        s_new = ''
        s_trans = ''

        se = s[0:len(s):2]
        so = s[1:len(s):2]

        se = sorted(se)
        so = sorted(so)

        for i in range(len(se)):
            if len(s) % 2 != 0 and i == len(se) - 1:
                s_new = s_new + se[i]
                break
            s_new = s_new + se[i] + so[i]
        
        for c in s_new:
            if ord(c) in range(ord('0'), ord('9') + 1) or ord(c) in range(ord('a'), ord('f') + 1) or ord(c) in range(ord('A'), ord('F') + 1):
                s_trans += hex(int((bin(int(c, 16))[2:].zfill(4))[::-1], 2)).upper()[2:]
            else:
                s_trans += c
        print(s_trans)
            
    except:
        break