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

bccdb
 z
 dfdeed
 aab
 y
 abac

import sys

def solve(oleg, igor):
    n = len(oleg)
    oleg = sorted(oleg)
    igor = sorted(igor, reverse=True)
    result = ""
    for char in range(n):
        if char % 2 == 0:
            result += oleg[char/2]
        else:
            result += igor[char/2]
    return result

if __name__ == "__main__":
    oleg = list(sys.stdin.readline().strip())
    igor = list(sys.stdin.readline().strip())
    print solve(oleg, igor)
