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

bccdb
 z
 dfdeed
 aab
 y
 abac

l1=list(input())
l2=list(input())
l1.sort()
l2.sort()
n=len(l1)
k=len(l1)-1
for i in range(0,n//2):
    print(l1[i],end='')
    print(l2[k-i],end='')
if(n%2!=0):
    print(l1[n//2])


