bcdef
abbbc
 z
y
 reddit
abcdef
 abc
aaa
 y
z
 cbxz
aaaa

bccdb
 z
 dfdeed
 aab
 y
 abac

s1 = sorted(input())
s2 = sorted(input(), reverse=True)
result = ''
for i in range(len(s1)):
    result += s1[i//2] if i%2==0 else s2[i//2]
print(result)
