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.sort()
t.sort()
n = len(s)
print "".join(s[i/2] if i % 2 == 0 else t[-(i/2)-1] for i in xrange(n))
