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

bccdb
 z
 dfdeed
 aab
 y
 abac

oleg = [c for c in input()]
igor = [c for c in input()]

oleg.sort()
igor.sort()

count = len(oleg)

o = 0
ig = -1

out = ""
for i in range(count // 2):
    out += oleg[o] + igor[ig]
    o += 1
    ig -= 1

if count % 2 == 1:
    out += oleg[o]

print(out)
 	 					   		 	  				  	   	