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

bccdb
 z
 dfdeed
 aab
 y
 abac

s = list(input())
t = list(input())
n = len(s)
ans = ""
i = 0
j = 0
s.sort()
t.sort()
while (i<n):
    ans += s[j]
    if (i+1<n):
        ans += t[n-j-1]
    j += 1
    i += 2
print(ans)
