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

bccdb
 z
 dfdeed
 aab
 y
 abac

S=input()
S1=input()
L=[]
L1=[]
for i in range(len(S)) :
    L.append(S[i])
    L1.append(S1[i])
L=sorted(L)
L1=sorted(L1)[::-1]
S=''
h=1
v=0
v1=0
for i in range(len(S1)) :
    if h%2!=0 :
        S=S+L[v]
        v+=1
        h+=1
    else :
        S=S+L1[v1]
        v1+=1
        h+=1
print(S)
    
