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

bccdb
 z
 dfdeed
 aab
 y
 abac

s=raw_input()
p=[s[i] for i in xrange(len(s))]
t=raw_input()
q=[t[i] for i in xrange(len(t))]
p.sort()
q.sort()
i=0
j=len(q)-1
c=0
ans=""
while c<len(s):
	if c%2:
		ans=ans+q[j]
		j=j-1

	else:
		ans=ans+p[i]
		i=i+1
	c=c+1
print ans