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

bccdb
 z
 dfdeed
 aab
 y
 abac

s = list(raw_input())
t = list(raw_input())
s = sorted(s)
t = sorted(t)
n = len(s)
ans = ['' for x in range(n)]
if n%2:
  s = s[:n/2+1]
  t = t[n/2+1:]
else:
  s = s[:n/2]
  t = t[n/2:]
t = t[::-1]
for i in range(n):
  if i%2:
    ans[i] = t[i/2]
  else:
    ans[i] = s[i/2]
print "".join(ans)