题解 | #字符串合并处理#

def rev(i):
    if i in '0123456789ABCDEFabcdef':
        bin_result = bin(int(i,16))[2:].rjust(4,'0')[::-1]
        decimal_val = int(bin_result, 2)
        hex_val = hex(decimal_val)[2:].upper()
        return hex_val
    else:
        return i

str1, str2 = input().split()
s = list(str1+str2)
s[::2] = sorted(s[::2])
s[1::2] = sorted(s[1::2])
result = ''
for i in s:
    result += rev(i)
print(result)