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

bccdb
 z
 dfdeed
 aab
 y
 abac


def func(lo,li):
    lis=[]
    xo=0
    yo=len(lo)-1
    for i in range(0,len(lo)):
        if(i)%2==0:
            lis.append(lo[xo])
            xo=xo+1
        else:
            lis.append(li[yo])
            yo=yo-1

    s=''
    for i in range(0,len(lis)):
        s=s+lis[i]
    print s

O=raw_input()
I=raw_input()

lo=[]
li=[]
for i in range(0,len(O)):
    li.append(I[i])
    lo.append(O[i])

lo.sort()
li.sort()
func(lo,li)
