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

bccdb
 z
 dfdeed
 aab
 y
 abac

oleg=''.join(sorted(raw_input()))
ing=''.join(sorted(raw_input(),reverse=True))
i=0
ans=''
n=len(oleg)

while(len(ans)<n):
    ans=ans+oleg[i]+ing[i]
    i+=1   
if(len(ans)==n):
    print ans
else:
    print ans[0:len(ans)-1]
        

